also, logical replication has some issues that make it not necessarily perfect for cross version migration: schema changes and sequence usages are not synced.

While schema changes are probably not much of a problem because that's something you can easily prevent during migration, sequence usage is because once you fail over to the logically replicated secondary, you will have to reset all sequences to their current values or all further inserts into tables with sequences will fail.

the other option, of course is to not use sequences but rather use UUIDs for your primary keys, but those have their other collection of issues