Possible - this is the RC release though.
Also, I really think it started when I added the extra 3 accounts after upgrading to plus.
(The app was a bit slow before upgrading to iOS 14.5 and adding the accounts but now it’s unusable levels of slow)
The last few releases have theoretically been addressing it but I’m still getting a lot of lag switching between connected accounts, and occasional crashes. Nothing quite as bad as whole phone overheating tho.
I can echo that the App is again, incredibly slow and even frustrating to use, and hogs battery. I have an iPhone 12 mini, iOS 14.5, and on Monzo Plus with a Connected account. I’ve got to the point now, where I don’t enjoy opening the app because it is so slow.