Need help understanding Marshall Plexis

so my local rehearsal studio has a Marshall SV20H Studio Vintage paired with a Hiwatt cabinet and i got it to sound like absolute trash LOL.
Im convinced that this issue is on my side for not being at all familiarized with plexis (played a boss katana my whole life)

my band plays alt-rock/post-rock type stuff so fuzz and reverb is very important, and i have a couple of pedals for this reason, but none of them sounded like they used to thru this amp, the sound of them got completely obliterated and it just sounded overall WRONG. I tried to keep all of the EQ knobs at noon.

So my question is: how to get a nice clean tone out of this amp that will be loud enough so i can actually hear myself with the drummer? does it always need to be cranked for this reason? paired a photo of the amp in question

https://preview.redd.it/55uyinlupi3e1.jpg?width=828&format=pjpg&auto=webp&s=bb808de0e352940cdfc6ddbca27ab04d4ce7b464