I've played lots of Halo 2 as part of the Master Chief Collection on Steam. It's a lot better than the box-release version. I couldn't even play Halo 2 standalone on PC without forcing vsync on via the Nvidia Control Panel, which is an option the game does not give you, or it misinterprets and mistimes all of its control inputs and you can't aim worth a damn.
MCC was allegedly an entirely fresh port by 343 without using either of the previously deficient PC ports. It is said the port/rewrite was a big part of 343 getting familiar enough with the engine(s), documenting what Bungie hadn't entirely documented and 343 hadn't pulled in as headcount in the messy divorce, and making the engine their own in the path to building Halo 5. In my experience that seems to track in that a lot of the "feel" changes from the original Xbox versions seem to me to align with how Halo 5 feels to me.
There's tons of videos that go into various levels of detail on its faults
https://youtu.be/03K2Uz3s1hg?si=zaFO1XdzMcFvI1F6