Sovereign targets STFs based on risc0. risc0 is a zkVM that implements RISC-V ISA. Being zkVM means that they can provide ZK proofs of execution. Sovereign doesn’t support ORs.
It’s likely easy to do a cargo-patchable Sovereign SDK shim, so that anything which runs on their chain could run on Frame in a parachain, except maybe a million times faster than on their risc0 zk roll up.
I am rather dubious that a) it’s really that easy b) makes sense c) that it will be that much “faster”. The throughput of a ZK rollup might not be limited by ZK proving that much. I say that because it seems to be possible to remove proving from the critical path and it also seems to be possible to parallelize it. Therefore, it then becomes mostly the question how much hardware you can throw on proving and how much latency you can tolerate.