Not sure what Lineage ships with, but i use the Fossify apps and have been happy with them. I always have to enable MMS for group chats in fossify messages though

LOS apps should be a good as any with Android, as it's stripped out the Google services. Won't support RCS though as that's a carrier thing that requires Google Services.

But the caller and contacts apps should be good to go!

if it actually makes a difference

The encryption part only works if the other person you are messaging with also uses this app.

Apart from that nothing looks wrong at first glance. I wouldn't use it yet only because it seems a little bit new (first git commit was in July). But that doesn't mean I think there is anything shady about it.