My vote will go for a modded EP Booster ..... one with a 9 -18 volt switch ... + 3 db switch ... bright switch .... and last but not least a Fat switch .
I like the Boss GE-7 for my "clean boost". I usually goose the mids a little, and bump up the output of course. It's not transparent, but I like the color it adds. There are a couple of components you can swap out to reduce noise without affecting the color too much.
The Suhr KoKo boost would be a good option here man. The left side is just clean boost, and you also get the mid boost added to it on the right side. Clean boost and a great high gain boost in one pedal. I honestly don’t ever use the clean boost side though