Not a Monzo Business customer (using Starling) but I absolutely love QuickFile and would recommend giving it a try to see if it meets your needs.
I moved over from Pandle, and the difference is night & day. As a relative novice at running my own part-time business - everything makes sense, the knowledgebase is excellent, it works well and is fast. Doing any finance or accounting used to be quite a chore, but now it’s not!
Transaction tagging, invoicing, recurring invoices - all good. You can email receipts, or there’s a Dropbox integration if that’s your thing.
I do most stuff on desktop, but the Android app is fine for checking in on things and doing the basics.
(I’ve added my 10% discount referral link to the wiki)