I know we all have different tastes, equipment (PA) and use scenarios (style of music, size of band, venue etc) but that definitely hasn’t been my experience. I have always found that the live sound with the Kemper is the best live sound I’ve ever had and spound guys generally love it when I give then a single XLR out and say “I’m good to go”. Most sound guys I’ve worked with also say it works great live and sits in the mix better than my real amp (partly because I’m able to keep the stage volume lower and still get a great sound so the onstage amp sound doesn’t restrict their mixing options as much). I did a gig on Saturday with my Powered Head and a Kabinet at low volume on stage so the rest of the band had something to work with but not so loud that it made the horns complain (which is a unique experience 🤣) and had most pf my own on stage sound via my In Ears. Once you get used to that there’s really no going back.
I wonder if the issue you are experiencing is more self doubt than reality. Our minds often play tricks on us and we start to hear problems that aren’t actually there. What did the audience and sound guy think?