Ohh, I understand now what you're saying. LOS (upstream) finally allowed uG to work on their images, though not pre-installed with them, it's mentioned on LOS4uG FAQ, see question Why do we need a custom build of LineageOS to have microG? Can't I install microG on the official LineageOS?, the answer includes a couple of references to LOS MRs. I was not aware of that, and that makes all derived ROMs inherit such ability from upstream LOS, including divestOS, so now I see what you were talking about. The answer in that FAQ doesn't indicate that the official F-Droid client can be installed, and even better neither it or it's lighter official client (that one never supported privileged extension) require privileged extensions to install apps in the background, so no need to install such extension through adb, and once installed the F-Droid client, one can add the microG repo to keep the uG apps up to date. Therefore no need for LOS4uG actually.
The sad thing is that divestOS images/ROMs are no more, since divestOS is dead. I hope LOS ports divestOS' boot locking/unlocking mechanism from the still available divestOS repos, that would make LOS even better.
The other sad thing is that as LOS4uG signs with its own keys, different than the LOS ones, once you start with such images, unless you can backup everything, apps, apps settings and contents, LOS settings, and so on, without a google account, you'll have to keep using it, until you change phone, or you are OK with a factory reset and having to set everything again, since moving to LOS implies different signatures and keys, which in turn implies factory reset and further cleanup to make the image work, :( That holds true if wanting to move to divestOS images as well.
Sorry I didn't understand what you were saying. I've been using LOS before it was named like that (cyanogen), and as far as I can remember when uG showed up, LOS decided it didn't want to support it, and it was until early last year that it decided to finally allow it, though not helping a bit providing it pre-installed, which is fine, because then the user can get to it, or rather Gapps. So I never read back about LOS criteria changing...
I second xmpp + omemo, and would caution that as far as I can remember matrix leaks significant metadata when syncing between instances/services.
As a personal decision I got away from signal (molly in fact) more than a year ago.
I'm also keep jami working with my family, particularly for things not requiring immediate response. It's a different beast, since it's p2p, but there's no server associated to it, no matter if decentralized or not. It's easy as well, just not as responsive, in particular if looking for immediate responses... I like and keep both, hoping jami improves.