You’d be effectively withdrawing to reinvest anyway, so that’s the route you have to go manually, and then choose which division of funds you want the withdrawn money to go in
I cannot see how withdrawing out of the ISA and then reinvesting into different funds would not impact my allowance.
I know that with Trading 212, for example, I can withdraw money from funds into cash, keeping the money within the ISA wrapper, and then use the available cash to invest into a different fund.
The Monzo route looks as if it would withdraw the cash from the chosen investment back into my current account, which is sub-optimal given that the money would then be double-counted against my ISA allowance if reinvested.
Similarly the ‘switch to different fund’ option only seems to allow me to move the entire investment in a particular fund into a different fund.
At present I have about 95% of my money invested in the one fund, with the remaining 5% split across eleven different funds. Surely there should be a simple and intuitive way to even this all out.