After fighting a long while trying to determine wether Firefox 98.0.2 has a slow startup of about 20 seconds the first time after booting, I have came to the conclussion that either with ubuntu repositories or with mozilla ppa repositories in both cases firefox is installled with snap and in both cases firefox (at least in my 22.04) last very much to load. and I have found a second bug and it is that when trying to backup or restore bookmarks firefox does not interact with caja and you cannot get latest backup or make a new one.
I have completely removed snapd and dependencies based upon some guide found in internet and after using mozilla ppa I installed via apt "firefox-esr" version 91. with is fast and reliable.
I am not yet aware what this version is but I guess it has an extended support release intended for enterprises.
In other words you must first get rid of snap and after that load mozilla ppa reposotiries
sudo add-apt-repository ppa:mozillateam/ppa -y sudo apt update sudo apt install firefox-esr
The fact is that this version works fast.
Hope this information is useful