Do you have default fillfactor set on this table? If not, I would wonder if reducing it to 50% or even 20% would allow many more HOT updates that would reduce bloat.
Also, is there any period of lower activity on your system that you could schedule a vacuum freeze for daily or weekly? I believe having frozen pages would also mean all the autovacuums would be able to skip more pages and therefore be faster.
>> autovacuum_vacuum_cost_delay = 20
This was changed to 2ms in PG12. You should reduce that most likely.