Mixer w/ audio interface built in?

Hello!

I’m looking to purchase an audio interface with enough inputs to track one guitar and drums! I was wondering if I should purchase an interface with 4 or more inputs and then a separate mixer or purchase a mixer with a built in interface…

I currently own a MOTU M4 which has 4 inputs but only 2 of them or mic/line inputs :(

If anyone has any advice on creating the most optimal setup to start recording full demos, any direction would be very much appreciated!