These are not general approved tips, but they work for me:
I'm also not super happy about my volume knob behaviour, but what generally helps in that regard is increasing compression within the amp menu (hold down amplifier, and I think the parameter is on the 1st or second page).
Ruefus already mentioned the Definition parameter, which is quite powerful. It does more than just increase treble when turning clockwise. Don't hesitate to increase it by several points (it's virtual, so what can go wrong?). It works really nicely to brighten up profiles and acommodate them to humbuckers. Tonejunkie has a great youtube tutorial on this specific parameter (and lots of others btw).
How do you monitor? Headphones, monitors, guitar cab, frfr cab? Huge impact here! I switched headphones and things sounded much better after that. I also plan to invest in Genelec monitors as I'm not super happy with my Yamaha HS8 (but that needs to be validated by wife first). I'm really looking forward to the Kemper Kabinet, which has been announced to Q3-Q4 this year. With the introduction of the stage and the programming sprint of the editor, I very much doubt that this will happen before 2020, but I don't care. As long as it comes out at some point
Volume / loudness is also really important. You need a certain loudness for profiles to come alife.
Commercial profiles:
I have what feels like a gazillion of profiles. Actually, it's a bit more than 2.500 profiles I believe. I filtered out a lot and have around 50 on my Kemper right now, which is still too much for my taste. I want to narrow that down to 20 max. My personal experience with Mbritt and Tonejunkie was also kind of meeh... I had to tweak a lot to make them sound good. And some packs just didn't work at all. When I discovered the loudness thing, I tried some MBritt profiles again and the sound was great. Kind of cool to rediscover awesome new profiles, which I filed away as meeh.
My favorite profile maker though is Bert Meulendijk. I just love his stuff and I almost do no tweaking to his profiles. As soon as he brings out a new pack, I buy it without even thinking about it. His last filmo pack has some sick clean / edge of breakup sounds in there. Bert has his rig pack in the righ manager, which is not super big (I think it's about 10 profiles), but it'll give you a quite good idea about his work. His first 2 packs and the Wisseloord pack contain my all time favorite profiles. In his rig pack, there's a fender showmaster which works great for me.
As mentioned above, these are just my personal opinions. The things I mention work with my guitar and give me sounds that I like.
Maybe some of these things will help your too!