Thunderbird Email Notifications?

My assertion of 'forced' was due to my own needs in preserving extensive archived content in local storage vs. which email client(s) are actually 100% capable of importing from TB -and- also play well with OAUTH2 as now REQUIRED by the big G - which leaves very little in the ways of choices.

Relates with this other thread:

My desire was to go from TB to Claws, but that ambition was misguided for pretty much all the same reasons.

Tried Geary - and it is perfectly horrid IMO - lobotomized to look good on phones with about zero in the ways of putting brain cells into it. Meh.

Evolution may be OK for use with non-G accounts, but also seems not to play nice anymore with those absolute OAUTH2 requirements.

As far as uninstalling my present TB - doing so will nullify an entire day's work of setting up the accounts & copying in all the archived stuff - UNLESS:
Perhaps it may be possible to preserve the profile data from V68.2.2 to 52.9.1 somehow ?? (No idea if they are too radically different ??)

Yes of course I have Synaptic & would prevent updating, if the rest of this as described is somehow possible ??

Thank You for replying so helpfully & thoughtfully to my plea for help !! :

Good luck sir.

All well wishes gratefully appreciated.