It really is, though. Ian Flynn was one of Frontiers writers after all, so I'd assume he'd have a better understanding of it than you do.
A: And yet he admitted on the Bumblekast two days ago that his statements about The End on Twitter were his own opinion, not any real official word.
Solaris can't die in his complete form. The only reason they could kill him was by temporarily knocking him unconscious so they could wipe his flame out of existence. The End on the other hand, whether you like it or not, is dead.
B: You literally just spouted nonsense and acted like it was fact. Literally nothing that you said here is true nor stated in any official material whatsoever. The small flame of hope IS Solaris' true and complete form that is explicitly stated truth and fact.
They had to destroy his consciousness so he wouldn't have complete control over time, but given that he's unkillable, they had to blow out his flame instead. Also, Super Shadow's time warping chaos abilities alongside Solaris' own attacks are the only things that can damage is 'armor', something that The End can't do.
C: Every Super character can damage Solaris' "armor" actually. Literally watching gamplay footage of it as I type this. Sonic literally does the most damage. Blowing out his flame wasn't due to him being unkillable, that is literal fan wanking, they did that because not doing so would just result in everything happening all over again in an endless cycle of destruction. They literally say so with NO mention of killing Solaris being in and of itself a reason for doing the deed.
By preparing all they had to do was find the Chaos Emeralds, in which they did for Solaris as well.
D: And in the Final Horizon, which IS canon, they had to do more.
Other way around actually, The End died, whereas Solaris can't die in his complete form and needed to be wiped from existence just to deal with him.
E: In other words, Solaris died, stayed dead, and can't return unlike The End who is explicitly stated in the SEGA approved official material to be able to do so. Quote from Frontiers: "You strike this incarnation with all your might. It changes nothing. You are not brave. You are not victorious. No matter what form I take. The End comes for you all."
I'm sick of seeing this inaccurate head canon used as a way to 'prove' that Solaris is weaker. Super Sonic and some robot killed The End, whereas Solaris needed Super Sonic, Super Shadow, and Super Silver just to be weakened. The fight with Solaris was literally not a '3 vs 3 situation' as shown in the game, all three of them go to fight the same Solaris at the same time, talk to each other throughout the boss, and all damage different parts of him that can be seen when playing as every character.
F: Oh, hi, Final Horizon the 100% canon other possibility of the final island. Also, quote by Silver directly from the game: "If you say it exist in the past, present, and future. Then I'll destroy them all at once!" Also, didn't you literally just try to claim that only Shadow could hurt Solaris? Kind of contradicting yourself there.
You seem to be forgetting that Solaris hadn't grown to his full power yet, Solaris' flame couldn't do much on its own as he hadn't finished developing yet, and it wasn't 'a small explosion' that separated him, Solaris was the explosion, and it was an experiment to gain control over time itself. It's not until Solaris finished developing that he'd be that powerful.
G: WOW! You literally JUST stole information from Frontiers, transplanted it onto Solaris, and mixed it with disinformation about 06! The End was the one in a weakened state after emerging, not Solaris, they literally said they had to beat it before it regained its true power and became truly unbeatable. Literally NOTHING of the sort was EVER said about Solaris. Solaris is the small flame Elise blew out at the end of the game, the explosion that split Solaris was the result of the experiment failing.
1. For starters, the whole "3 vs 3 battle" thing is not true, as there's only one Solaris who's not bound to any specific time, and it's shown both in the cutscenes and in game that they're all fighting the same Solaris.
H: The whole reason they brought Sonic back was because just Shadow and Silver would only deal with two of the three Solaris. One again, quotes from Eggman, Silver, and Shadow:
Eggman: No. It is a transcendent lifeform that exists in the past, present, and future. Defeating it here, now, would do nothing.
Silver: "If you say it exists in the past, present, and future. Then I'll destroy them all at once!"
Shadow: "It might have been possible. If he were still alive."
If there was only ONE Solaris, then they wouldn't have highlighted this fact nor pointed out the NEED for Sonic at all. That is just an undisputable fact. The reason you're fighting only ONE in GAMEPLAY is purely for the sake of the player. Canonically, they are each fighting their own Solaris. All controlled by a single consciousness.
1. Outside of that, nothing ever said that The End can freely travel dimensions, and another thing that I'd like to note is that they say in the boss that Solaris isn't tied into any dimension, so it'd be impossible to seal him away as his mere presence shatters dimensions.
I: Oh, hi, base game and Final Horizon Ouranos where The End is implicitly shown emerging from Cyber Space within Supreme. As well as the fact that the literal wall around Cyber Space (described by The End multiple times as a wall between dimensions) propped up by the Titans and six towers on Rhea, all powered by the Chaos Emeralds, are what keep The End from travelling between dimensions and just leaving to continue its ambitions. All of which is explicitly stated in Frontiers.
Also, Eggman LITERALLY says at the beginning of the fight that Solaris is anchoring himself to Sonic's dimension. A.k.a his consciousness. Literally watching gameplay footage to verify your claims, and I am not shocked that it's disproving everything you've claimed thus far.
Also, what Eggman said was that they can't stop its FORM since Solaris' mind would just keep resurrecting it. Hence why they had to attack the core and kill his mind. You literally hear Mephiles faintly screaming "NO" in the background at the end. He is NOT falling unconscious as you're claiming.
Also, also, how did Mephiles and Iblis get sealed if they're both supposedly beyond dimensions? Heck, how was Solaris even contained enough to be kept like an heirloom or experimented on if he's beyond dimensions and able to shatter them with his mere presence as you claim?
Do you see how your claims don't make sense with the source material?
1. Another thing I'd like to note is that while this is something that The End can also do, as far as I'm concerned Solaris, Dark Gaia, the Egg Salamander, the Egg Wizard, and The End are the only villains that can actually hurt Super Sonic.
J: Well, yeah, THAT goes without saying. No argument there. Though, you DO know that The End's attacks either one hit kill (base game) or shave off 30 rings from Super Sonic (Final Horizon), right? Which is way more than any other boss. Heck, Solaris only shaves off like 10 rings (gameplay footage confirms that, jumped from 41 to 31 after getting hit). Not to mention that it's managed to do what Solaris and all those other bosses couldn't and not only overpower but also DEPOWER not just base Super Sonic but Super Sonic 2, an ENHANCED Super Sonic, in one attack.