Why many more deadlocks after upgrade to PG 17.5?

RHEL 8.10

Prior version: 14.18

There were deadlocks when at PG 14, but a small fraction of the current number of deadlocks.

All tables were vacuumed and analyzed immediately after the pg_upgrade. 😉

Tables are partitioned by range (weekly).  Physical replication; no logical replication.

  There have been no code changes since the pg_upgrade (performed 9 nights ago).

Attached is a section of the PG log file.  It's the same kind of deadlock, in the same code as before; just now there are _more_ of them.

I don't control the schema or the application, or the code in the application; we just need to know why there would be _more_ in 17.5 than in 14.18.