Fedora decided with release 27 to enable trim by default on newly created encrypted devices. I was not happy about this decision and try to make some noise but nobody really seem to care. There is a reason that it is disabled by default in the Linux kernel, and making this kind of decision on behalf of the users without any input from the community is pretty fucked up.

Personally, I would like to explore the idea of a secure enclave that keeps a map of which blocks are in use that gets referred to during write operations. This seems like a problem that is going to need to be solved with hardware.

Yes, it can be, and it's already present.

Oops, probably should have checked before asking