My Ender 3 came with a Mean Well PSU, like what i believe the pro does though mine isn't a pro. I liked the way the tools were held it was just too wide for my PSU, so i just took the design and made it narrower. It sits on a Mean Well LRS-350-24. Because of the Smaller size the spot where the nippers would sit under it wouldn't work, i didn't particularly need that so i didn't try to add a spot for it. It slightly covers the PSU fan but it isn't a lot so i'm not worried about it. Thanks to Pickle_Rick_1 for the original design. In the picture of it on the bed It has a lip on one end from the original design. Upon printing it i realized that wouldn't work as that edge does not protrude past the printer like the regular PSU does, in the provided STL that feature is removed so there is no lip. So i have not printed this exact STL (i just nipped the lip off mine) but i sliced it to check it and as i didn't change any other measurements i have little doubt it would be fine.
I don't think you actually need support but i supported the center of the screwdriver hole, i printed it upside down.