Hi and welcome to RO.

This is the problem with taking a board mix and has nothing to do with the XL1. You would have gotten the exact same mix no matter what recording medium you used.

The thing people seem to forget about recording directly from the PA Mains output, is that the loudest thing(s) on stage require relatively little amplification - so they're sending a relatively small signal (if any) through the mixer. The proportional volumes of the band will be perfectly upside-down. Consider this, if the guitar player has a Marshall stack and the bass player has an Ampeg SVT they can each blast 120dB or more from the stage without any help from the PA. The rest of the instruments (lead vocals, keyboard, drums) will have to be heavily amplified just to keep up. In which case, the only guitar and bass that will make it to the recording would be whatever bleeds into the vocal mics etc. Which sounds exactly what you're describing.

So if you can't improve it enough with EQ it is, as you say, 'final'.

Next time try connecting to a Matrix output if the mixer has it, or an Aux out (or two). Jam some closed-back headphones on and try to balance things out to the best of your ability during the live performance. Until you're ready to truly multi-track, that is the next best thing.

Best of luck.