It really is the worst and most awful decision that RISC-V absolutely must retract, the sooner the better. We cannot have performance and compressed at the same time. There are other things about the C extension that make it extremely bad for emulators too.
The good news is that we can ignore rv64gc completely and just build everything rv64g, if you control everything yourself. Personally for my RISC-V use I actully do control everything and because of this I can pretend the C-extension doesn't exist.
I don't know if any of these have RISC-V support, but I would be interested in hearing about it. I would actually love a good distro for RV32G which is arguably a better match for FPGA softcores (and dev boards with > 4 GiB of external memory are rare)
The good news is that we can ignore rv64gc completely and just build everything rv64g, if you control everything yourself. Personally for my RISC-V use I actully do control everything and because of this I can pretend the C-extension doesn't exist.