It makes more sense that he did consider switching sides, but then saw how obviously shady they were and decided to investigate them instead of switching sides.

I knew a genius wouldn't be fully manipulated by such a shady organization.

Ah. Such a good man. He can't even bend the truth. The information broker did SAY, specifically SAY he did not have information on the one who makes the chokers. He also SAID all information he found on that guy was false. Stating that fact is not lying. Therefore one can use that truth in full sincerity...

Am I an asshole?

Well. Instead of risking his life, he could have set a laboratory nearby, with a extension on site and try to use that extension to kill the fungus and... Well. I know. If it was actually a curse, that won't work. But he did break the scientific method by not even trying!

My opinion on the lead mellowed a bit as the story advanced tbh.

Is he... Correcting💢💢💢 a brat💢💢💢?

Controlled heart? Nah. He's doing it for free!

Time, and the fact that he had scheduled the end for last year and had to take another year to end it. When they exceed the planned deadline, they start to get pressured by editors.

I think he can't fix it anymore.

Pretty much. Yes! He focused so much in Sukuna and Kenjaku that by the time the editors were telling him to wrap it up he didn't get enough time to make a better ending.

Well. You see. The manga did rise the stakes a lot. It did point at something that would be very extreme, with a main antagonist who basically was undefeatable. That could lead to only three paths.
1. Villain wins. Impossible in a battle shounen like this one.
2. An epic final battle with a cathartic ending. This option however is harder to attain when you already have a deadline for the finale, you have a battle shounen with editors on your back, and killed off key characters while developing the villain more than the hero.
3. What we got.
Most people expected 1 or 2. 3 was the most logical outcome.

Yes. You just didn't notice because you had different expectations.

No. It was exactly what JJK was pointing toward from the previous arc. Your expectations were wrong,

No. I meant the pregnant wife.

Here I am laughing at all those who now say the ending is bad. No. The ending is good. What is bad is the parts before it. Same as with My Hero Academia.

Normally that's left for near the end...

Too many intrigues at once.

She has literally evaded the worst possible fates by being comic relief.

The tone doesn't fit the previous arcs. Saw this coming too. And people saying it's bad... Yes. It is... But not by itself. The problem is the previous arcs were a poor match for the overall series.

That parting sentence fits perfectly.