I have a distinct feeling that some people are going to hate this finale based on the discussions of the last few days. As someone who kept swinging back and forth about the logical conclusion, I think I might be a bit more welcoming to what was ultimately revealed than perhaps some others.
It was Kang all along.
What, no cheery jingle? Right, different show.
Loki and Sylvie reached inside the citadel at the end of time and they found some hard truths. The audience has to face them, too. The show was always about Loki and what that means for not just him but for all of his variants. However, despite the sudden shift towards Kang, I would argue that the crux of the show still remains about Loki because the seismic shift of all of time occurred because of the actions of one variant, while leaving another having to deal with the immediate consequences of those actions. I fully expect that dynamic will be the set-up for season two, thus maintaining the focus on Loki.
As for Kang himself, I was initially surprised how goofy and lackadaisical he appeared and I expected him to drop the façade at any moment to reveal his true nature. Instead, unsurprisingly, it turned he was just a variant and we have yet to meet the real future big bad. I know some people will hate the exposition dump that occurred in the middle of the episode, which caused the momentum that lead into the finale to crash to a startling halt, but I found Jonathan Majors' performance was just engaging and off-putting enough to make that heavy dialogue flow.
I was a little disappointed (but also unsurprised) that Loki and Sylvie ended up fighting each other, but it also felt right because, as noted, one could not trust and the other could not be trusted. I was also not surprised (but delighted!) that Sylvie used Loki's obvious affection for her against him so that the kiss we all knew that was coming was utilized as a distraction to maneuver him back to the TVA. Whether or not she actually returns that affection is yet to be seen and I'm certain that will be explored in the second season.
The one thing that did surprise me (but shouldn't have) is that Mobius and B-15 no longer remember Loki, the first of many consequences of Sylvie's killing of the Kang variant. It seems that Mobius may have become the de facto leader of this new version of the TVA considering Ravonna fled to parts unknown. I'm pretty certain at this point that she was just in the dark as everyone else about Kang (but had her own suspicions for longer), so I'm curious to see what she is planning to do next season. I'm also curious to know what files Miss Minutes gave her instead of the files Ravonna requested.
I love how we got the Tim Burton's Planet of the Apes cliffhanger with the statues of the Time Keepers replaced with the statue of Kang the Conqueror (somewhat fitting considering I just started reading the original novel for the first time last night).
Even though it wasn't directly stated, it's clear now this is what causes The Multiverse of Madness, as well as the rumored scenario of No Way Home. I will also take this as a confirmation to my previous musing that What If...? is a direct result of the season finale as hinted by Uatu's "vast new realities" line. I know all of this probably isn't a surprise to anyone, but most of us expected this would've been kicked off by the dissolution of the TVA and not because of the killing of a Kang variant, thus causing the rise (or return?) of Kang the Conqueror.
One thing that wasn't confirmed but still heavily hinted at: The citadel at the end of time definitely looks like it exists in the Quantum Realm. Undoubtedly that'll be confirmed in Quantumania.