Postgres 12 update to new major version

Hello all,

I have a question regarding the update of the production database (multiple
TB of data) from version 12 to higher major version. We would like to jump
to 15 or 16. DB is installed on a Linux server with one replica on another,
it is not on cloud.

First question is should we perform updates one by one? 12 -> 13 -> 14 etc.
or is it viable to jump to 16 right away? (We have few functions but
usually its plain tables)

Second we are contemplating options for the update since we are limited
with downtime. We could get 4 hours of downtime for the whole update
(either via pg_update or dumps). We are not sure how to estimate the time
for direct update or dumps. What would be the recommended way for it?

One option we see could be logical replication to the new major version on
a new machine, but we received feedback that in our setup it might not be
recommendable. Does it make sense to try logical replica? What would be the
downsides of it?

Best regards,
Boris Dovčík