There are lots of similiar trays that are well designed but the ones i liked either missed some features or where poorly edited from other stl's and/or designed to thick with to long print times.

I made this one thin enough that you print it with enough walls and top/bottom to make it solid.

I printed with 0,4mm nozzle and 0,2mm layer height

Tray can be printed without supports. (I used PETG)

Backplate is glued to the tray (I used clear PETG to let lighting in to tray)

Inserts smooth or with ribs from flexible material (I used TPU 95A)

Happy printing!