I think that volte is supported on some handsets. Not quite sure, though, as it requires the patented AMR-WB codec.
Cyanogen was a commercial entity and imploded because maintaining an OS is expensive and it was not quite the right entity for the job. But the efforts of the free software community were not lost and live in lineage os, which is probably a better shell for that project. This being said, more drama will probably happen in the future: Google is not likely to let to many escape a surveillance program that let them profit handsomely from advertisement fees. But I would say: so what? Keeping a working phone is a constant battle anyway. The networks change (protocols and frequencies), the devices only live a few years and the OS needs security updates all the time. The solution of the industry is that the customer should pay for a new device every so many months (and racks in a few hundreds in adds, apps and music subscriptions each year). The solution of the free software community is lots of drama every so many months.
Apple lets you live with a one time tax on the device itself if you don’t use their cloud services. It is probably the option with the least drama.