wal archiving is piss easy. you can also just use basebackup. with postgres 17 it is easier than ever with incremental backup feature.

you don't need horizontal scalability when a single server can have 384 cpu real cores, 6TB of ram, some petabytes of pcie5 ssd, 100Gbps NIC.

for tuning postgres parameters, you can start by using pgtune.leopard.in.ua or pgconfig.org.

upgrading major version is piss easy since postgres 10 or so. just a single command.

you do not need pgbouncer if your database adapter library already provide the database pool functionality (most of them do).

for me maintained database also need that same amount of effort, due to shitty documents and garbage user interfaces (all aws, gcp or azure is the same), not to mention they change all the time.