Simple jack for "thin" beds, mine is concave in the middle, with this I can level it.
Apply thermal insulation on the "pad" part (cork, neoprene).
Insert an M5 nut and its screw on the "jack" part.
Use a pair of 8 mm rigid pipes/rods.
Place the supports with t-nuts and screws.
I strongly discourage the use of pla, at least for "pad" part.