The reason I switched to Betterbird is the features I used daily were removed from Thunderbird 102.11.

I installed Betterbird in /opt/Betterbird since it is not OpenSUSE code.

Here's what else is coming to Betterbird that is no longer in Thunderbird - from their website https://www.betterbird.eu/ :

Betterbird 115 "Superstar" is coming

Unlike Thunderbird, we're not calling it "Supernova" because that sounds too much like descruction, see Wikipedia: "... a powerful and luminous explosion of a star turning the original star into a neutron star or black hole, or completely destroying it".

One very disconcerting trend is becoming clear: More and more functionality that existed for decades is being removed from Thunderbird. Of course we will endeavour to restore it in Betterbird:

    Total and unread/selected count removed from status bar. Yes, it's definetely gone!
    Can't select multiple folders any more for bulk processing. Yes, it's definetely gone!
    Can't use context menu on a different folder without losing focus on the current folder. Gone (so far)!
    No more connecting lines in threaded view: Yes, they are gone (so far)!
    The new card view, a poor implementation of a true multi-line view, can't the threaded. Not so useful.

We have integrated all our features and fixes into the Thunderbird 115 codebase and are now waiting for that codebase to stabilise. There are currently (16th May 2023) about 160 open bugs, see report here. That's down from a peak of about 200 bugs, some of which have simply be closed as "wont fix".