DROP OWNED BY fails with #53200: ERROR: out of shared memory

I'm trying to DROP a ROLE that has 4 schemas:
* 2 smallish ones (1 or 2 dozen tables each),
* 2 largish ones (250 tables, totalling around 4000 columns each).

And of course there are various indexes, constraints, etc... on each schema.

This fails with:

DDL Error: DROP OWNED BY "Epos-PNS (a73e1fbdcc5b4460ba55703a0d6b6ad7)"
CASCADE: #53200: ERROR: out of shared memory
HINT: You might need to increase max_locks_per_transaction.

And please note that there could be dozens even hundreds of largish schemas
associated to the dropped ROLE (2 + N), not just the 2+2 it fails with here.

So how can I determine a max_locks_per_transaction, when the number of
tables is basically unbounded?

From a PostgreSQL newbie perspective, this feels like a serious limitation
of DROP OWNED BY,
if it is limited by how many schemas/tables it has to DROP.

Will I need to DROP each larguish schema individually???

Thanks for any guidance. --DD

PS: Also note that in this case, the SCHEMAS are mostly empty (just ~ 200
rows per schema).
But in production, there could be thousands / millions of rows per SCHEMA.