Do Chromium browsers support Sidebery or some analogue of it?

Also, never encountered at least most of these issues, while working with several thousands of tabs.
In particular, previous session restoration hasn't failed me yet. Did you, by any chance, open several windows and close them one-by-one?

If you weren't already using some type of local or remote blocking with chrome... You should with any browser. You can use DNS or a firewall to prevent any browser (and extensions therein) from phoning home and/or serving you bullshit.

Base Firefox is pretty terrible but with the right addons you can turn it into whatever you want. I'm more privacy focused so all my stuff is aimed at that. Definitely look up something like arkenfox (https://github.com/arkenfox/user.js) to get a sense of all the bullshit options you need to turn off.

Someone else mentioned Librewolf but there's also Palemoon:

https://www.palemoon.org/

and Orion by the Kagi people:

https://kagi.com/orion/

Brave is dogshit for privacy. If you need recommendations on addons feel free to ask. Definitely start with uBlock Origin. Its legitimately the best thing on the internet.

I have an old laptop and ff ran really bad on it, especially with ublock installed. I'm forced to use chrome, so far I've been happy with it, but it sucks being saddled with more google slop.

If you want minimal disruption from your existing workflow then use https://github.com/ungoogled-software/ungoogled-chromium. They are currently maintaining manifest v2 functionality.

Since I keep mentioning privacy this is probably a good guide to post:

https://www.privacytools.io/private-browser

I've moved to Zen since Firefox started to enshitify

https://zen-browser.app/

I just can't imagine caring about the idiosyncrasies of web browsers

I do have issues with it taking a while to start, but other than that, I have had no issues. I have turned off AI and ads and they have stayed off. On my 64gb system it uses 0.5 gb of memory. Profiles currently is bad, but there is an update that fixes it soon. In the meantime you can group tabs together and it will remember them in between restarts (Though not between updates, which is annoying).

I switched to Vivaldi after a similar thread a few months ago and I couldn't be happier.

Yeah, the default Firefox experience was pretty bad when I tried it out recently. I'm back on Chrome for now since ublock lite seems to work fine getting rid of youtube ads (The primary reason I tried switching in the first place, since chrome now blocks regular ublock origin). If I ever make a serious attempt to try again, I'll try some of the changes suggested here.

As others users have commented, FF crashing is very strange. I've only had it crash when programming a WebGPU site on Nightly, and I've been using it for like 10 years. Though it is true that I don't like keeping many tabs open

I use Mullvad Browser, which i believe is based on Tor Browser which is based on Firefox ESR. The defaults aren't the most comfy, but I like that I'm mostly relaxing the default policy instead of patching holes.

I agree that base Firefox is not that good, I hope u find a good downstream that works for u.

this should solve your session woes; i've had the same probem in recent versions.

as for the rest of those issues, settings and about:config tweaking can solve those problems, but imo you're probably better off using a soft fork that does that automatically like waterfox, floorp, librewolf, etc.