I designed this holder when I knew a lot less about printing than I know now and I was still using an Ender 3V2. At the time, I felt that supports must NEVER be used. So I built the front plate separately and then made some PLA rivets to hold it on. It was pretty clever in its on way, did the job of holding my meter up off the bench when I was using it that way instead of carrying it to a job site.

I'm not sure that tree supports even existed then. This time I decided to give it a try using those tree supports (to the build plate only!) and in the auto-tree option. 
I cannot tell you how please I am. I'm only using them on the slot across the front of the meter. I broke off the trees and barely touched the tree remnants with my small triangular file. Wonderful. Smooth as butter!

Other than that, I used no supports and no brims. I chose the Gyroid pattern because everyone says to. Everything else is just default. I used 15% infill.
I think I'll make another model with probe pockets on the case itself. I used PLA which is about all I ever use. Have fun.