If you have a search there are dozens of threads with all these questions answered.
The 4% Monzo pot will update when Monzo change the rate. Lately this has been on the same day that BoE change the base rate.
The 1.81% pots are not controlled by Monzo. They should update but don’t always, the suppliers don’t have to move you and obviously prefer to keep you at a lower rate. Keeping them for transaction history rather than upgrading to a higher rate is one of the more bizarre things I’ve seen on this forum.