The more I listen the less happy I am with what i hear. [...] So where to start? [...]
In case this may help, RickWillitts, my advice is first think what you're really looking for. IMHO, there's not such thing as a good guitar tone, nor the best guitar tone.
There are two very different steps instead: first building a good PA band tone, in which your guitar is only a part, and second finding a stage tone which really helps your playing (not the more glamorous tone, nor hifi tone). For, sadly, you'll never be listening in the audience while playing on stage.
BTW being confident with the PA mixing guy may bring significant help in your quest. And some “in the room“ recordings too (with a well placed very good microphone pair, not mixer output recordings).
IMOE, a good i.e.m. may bring you much farther than any frfr ever will (i.e. mine is Westone Audio ampro30). Last, but not least, with i.e.m., a little “weakness“ in bass is often welcome, cause during a real world gig, you will “feel“ much bass coming from rear side of PA.
Have a good time playing and share good vibes around.