I stopped using every messenger besides signal and Matrix. Even my not tech savy parents are using signal now - its in my opinion the better solution to stand your ground and may push others into using the better apps
Did you tried DivestOS? Its my favorite Rom for the op6
OnePlus 6 and 6T had really broad custom Rom support, it is till now one of the best Phones for linux(pmOS) With some Roms you can even relock the bootloader
Events is missing Gancio. Its worth a look :)