OP you can mix and match whatever rings you want up front. as long as they fit. but a 2 teeth difference up front is less than 5% difference in gearing. if you went to a 55 it would at least have been 10%, and thats a difference.
unless you try it you will never know.

same in the rear. a 28 and a 30 is close. but you will feel the difference.

Personally I'm on 1x. thats all i need. i run a 42 or 44 up front. and a 40 for the winter/snowbike.