I'm a Firefox user for about 20yrs (since Firefox 3);

but too often I have to use Chrome, as so many sites only work properly on it; Firefox is really buggy or laggy on those websites;

For a time, all those AI chat web pages were just very slow on Firefox even with very little context, whereas Chrome only gets laggy when there is a lot of context.

Are you really sure it’s not because of an add-on? If I remember correctly, Mozilla has said that about 95% of all pages that don’t work aren’t due to Firefox, but to an add-on. I use Firefox exclusively and don’t usually notice that pages don’t work. When that happens, as I said, it’s almost always an add-on that’s to blame. And I dont notice its buggy or laggy. So could be good check your addons next time.

Here are some cases where Firefox really sucks: some of them are specific CSS styles, some are downgraded features, and some of them I just don't know why. As I mentioned here, the ChatGPT web and Gemini web used to be very laggy for no reason—or maybe it was just a bug for me?

I don't think any of this is caused by add-ons, though.

But it's getting better, and most of those problems are just gone;

Still, I keep Chrome around just in case.

You can report websites that don't work, or block Firefox, to Mozilla at https://webcompat.com/. Mozilla engineers try to reach out to the website developers or ship site-specific workarounds in Firefox.

Same here, but when a site completely fails in Firefox I either A) use my phone because mobile Firefox occasionally works or B) use Ungoogled Chromium.

https://github.com/ungoogled-software/ungoogled-chromium

Really hoping the uBlock will continue to work on that project...

How many extensions do you use on laggy FF?

Not using many extensions on my case, but Google meet remains unusable for a long time, sound is horrible during meetings. Chrome on the other hand works fine

So use Chrome for Google services and Firefox for everything else?

only site that was slow on firefox was google meet, but then it turned out someone documented how google had code to explicitly do that. ouch.