I disagree, there is low-hanging fruit Firefox is leaving on the table. The main thing that comes to mind is tab unloading. They don't unload tabs automatically like chrome can.
I was pleasantly surprised at the tab unloading settings under "memory saver" in ungoogled-chromium.
Firefox has been unloading tabs for several months or so (at least on nightly).
Firefox unloads tabs under memory pressure since more than 4 years: https://hacks.mozilla.org/2021/10/tab-unloading-in-firefox-9...
It is a naive and suboptimal implementation, they even describe it in the link you posted
"We have now approached the problem again by refining our low-memory detection and tab selection algorithm and narrowing the action to the case where we are sure we’re providing a user benefit: if the browser is about to crash."
I would prefer FF to be more proactive in unloading tabs way before "its about to crash" to keep system level memory pressure lower. Firefox is the main memory hog on my M1 mac.
Chrome can do this, there is no reason we should be stuck with "manual tab unload" and "unload when the browser is about to crash".
I am using an extension, but that just reinforces the argument: they could be doing much more here.
I believe that Firefox does it but not as frequently as Chrome does, but don't quote me on it. However, I am using a "tab suspender" addon on firefox to control how fast the unloading happens on tabs that are not active.
Indeed, I am using something similar "auto tab discard".