Would be nice to have something that integrates with 7z - it supports a lot of weird archive types, including "weird" ones I care about (for example PE files, better known as ".exe files").
Ratarmount also works for that. However, it, and any other tool I know of, works only well if it was compressed with pzstd because of a limitation of the zstd format. It needs separate zstd frames for fast seeking.