On these pages, it should be mentioned that DROP TRIGGER acquires an ACCESSEXCLUSIVE lock:
<https://www.postgresql.org/docs/current/explicit-locking.html>https://www.postgresql.org/docs/16/explicit-locking.html#LOCKING-TABLES
https://www.postgresql.org/docs/16/sql-droptrigger.html<https://www.postgresql.org/docs/current/sql-droptrigger.html>