For what you want to do a separate DSP just might be what you need to use. I’m sort of in the same boat you are with no real ambition to compete but really enjoy my music. I have a 3way up front with one 15 IB run off of 2 4ch amps & a Dayton DSP. I’d highly recommend that particular DSP as it’s fairly inexpensive but has decent features for the dollar... the Mini DSP might be an option for you as well, and I’ve heard several cars that incorporate it with Dirac that sound phenomenal.
I have my mids & tweets running of a 110w x 4 amp and the other amp running 225x2 at 2ohms for midbasses & 450x1 bridged for my sub and it gets stupid loud (for me anyway) and sounds pretty darned good... at least I think so.
I’d like to think you could do 2 4ch amps (1 to mids/tweets & 1 bridged to MBs) and a 3rd big boy for your sub(s) with either the Dayton or MiniDSP, or any other DSP you choose with at least 8 outputs, and be very happy. There are SO many options out there, you just gotta keep learnin, listenin, and researchin until you find what fits you & your budget.
And hit up a meet or 2 or see if there’s any members near you that wanna meet up for a demo session.