I believe the accounts screen is currently going through a redesign but the current account “switcher” is a bit cumbersome.
I think it would be good if you tapped on the accounts button, whilst already in the accounts screen then it would bring up the switcher. This would have the advantage that your finger is already in the right part of the screen to select the right account.
I came here to request the same feature. Switching between accounts should be a prominent feature, in my opinion and use case. I juggle between my joint and current account routinely and having to dig through menus to do this is quite annoying.
Switching between current and joint accounts is 4 clicks on Android. Monzo, would you care optimizing account switch workflow? Current implementation is really bad.