Speaking of 'works best in Firefox'... I mainly use Chrome (kinda have to), and it's practically impossible to use it for reviewing big GitHub PRs with many files changed (UI just freezes), but everything's perfectly fine in Firefox!
Could this be a subjective experience? Is it reproducible on multiple machines? And have you tried it with a new profile?
Well, many people have complained about this very issue, and it was actually from this [1] discussion that I learned that Firefox handles big PRs just fine. No amount of jumping through hoops, including creating a new profile, helped to make it work in Chrome.
Our CTO was giving a hybrid presentation in a conference room on zoom, and his M3 Mac kept complaining of high memory usage. Chrome was rated at taking 60GB of memory.
No single consumer application should be taking over 60gb of memory.