So maybe my experience is unique but websites don't always test with Firefox now and some simply don't work with it. I use it anyway out of principle but occasionally I need to open Chrome.
On mobile it's even worse. Firefox is stuttery on my Pixel 8 Pro and doesn't handle more than ~20 open tabs well. The nightly version fixes the stutter but crashes all the time (it's a nightly build after all so this is expected).
Just ublock origin with default configuration. My complaints aren't for page loading so much as scrolling. Stutter when scrolling is really annoying to me. Interestingly as mentioned the nightly version fixes this, even when ublock is also installed on it.
My occasional page related complaints are for stuff animating correctly. This is very rare and a minor inconvenience usually, but sometimes stops you from being able to do what you came to accomplish (usually on jank websites, rental car companies for example).
Pretending Firefox mobile is already great is counterproductive to fixing it's issues. They don't have extensive development resources particularly for the mobile version so it makes sense it's worse. But to a non-techie switching to it isn't a good experience yet. It definitely can be in the future but without at least acknowledging it's current flaws why would anyone switch who has previously tried switching?
Odd it's desktop Firefox/Librewolf for me that has all the issues instead of mobile Firefox/Fennec. But yeah. Unfortunately Firefox laid off a lot of their developers a few years back and it's starting to catch up to them now.
But I don't like the above post being down voted. Yes use gecko if you can, but but down voteing for somebody stating the objective fact that gecko is starting to lag behind isn't going to help it get better.
This is just straight-up slander. I've been using Firefox since 1.0PR (so for 20 years now). It was a very rare occasion when a website wouldn't function properly, and almost never would a website completely break. I haven't had a single issue with a website in Firefox for over 5 years now. I would appreciate it if you could post some examples of some websites that "simply won't work with it", because I simply don't believe you.
Mobile is fine too. I have a bad habit of not closing tabs. It's gotten so bad that the tab count number is just the infinity symbol on my phone. Still don't have any slowdown issues on a Fold 3. Didn't have any on my OnePlus 6T, either, nor my LG G2, nor my Galaxy S3. Quit making shit up just to have an excuse to stick with a shitty browser.
Ah yes, anything institutional or governmental tends to behind on the times when it comes to browser compatibility. Good point.
I remember back when I tried to get assistance from my local government; the application form didn't work unless you had IE6 (a browser that hasn't been supported since Windows XP), in 2012.