I have an up to date Firefox and Thunderbird in Debian.
Here is what my dot files look like
nevj@mary:~$ ls -l .mozilla total 12 drwx------ 2 nevj nevj 4096 Jan 28 2021 extensions drwx------ 6 nevj nevj 4096 Jan 28 2021 firefox drwx------ 2 nevj nevj 4096 Jan 28 2021 systemextensionsdev nevj@mary:~$ ls -l .thunderbird total 24 drwx------ 13 nevj nevj 4096 Apr 19 21:57 6ozfwg4n.default-default drwx------ 3 nevj nevj 4096 Apr 19 19:59 'Crash Reports' drwx------ 2 nevj nevj 4096 Feb 15 2021 gainyiif.default -rw-r--r-- 1 nevj nevj 62 Feb 15 2021 installs.ini drwx------ 2 nevj nevj 4096 Feb 15 2021 'Pending Pings' -rw-r--r-- 1 nevj nevj 259 Feb 15 2021 profiles.ini
So do you have all those directories and files in the files you copied in?
My Firefox is 98.1.0esr(64-bit) Thunderbird is 91.8…0(64-bit)
I dont know of any recent changes in the way .mozilla or .thunderbird are arranged.
If yours are the same… you must have to do something to Firefox to get it to look at uploaded config files instead of starting out as a new user.
Neville