Sounding like a broken record at this point but it used to be chat as in the staff member was actively engaged in the conversation until it was resolved. All done in one sitting.
It’s now more might be 5 mins between replies, might be 5 days. You might have one person dealing with it, you might have 10.
It should be Monzo PenPal. 
Anyway based on the other ongoing thread it looks like Monzo might be doing something about it.
Also it’s always best to have more than one bank regardless if you’re with Monzo or not.