If I'm allowed to make a critique, I'd say that the module doesn't look very much like Go. The (ab)use of generics and having every policy to its own package feel a little over-engineered.
I might be slightly biased, because, not knowing about this project, I implemented half of the functionality in my own simpler module: https://git.sr.ht/~mariusor/ssm
I might be slightly biased, because, not knowing about this project, I implemented half of the functionality in my own simpler module: https://git.sr.ht/~mariusor/ssm