I've drafted a patch which I think improves things, but it probably needs more work and opinions.
Seems we can improve things by simply removing the "rule of thumb" sentence altogether. The prior paragraph states the things the queryid depends upon at the level of detail the reader needs.
The sentence "Two servers participating in replication based on physical WAL replay can be expected to have identical queryid values for the same query." apparently assumes that to participate both servers must share the same machine architecture. I am under the impression that this is only an advisory, not a requirement. Rather, two servers participating in physical replication will be ensured that the catalog metadata and major versions are identical. This is not the case for servers related via logical replication.