Do you want to disconnect the black parts? Assuming some elasticity in the black parts, I would add a ridge/edge to the black piece to wrap around the edge of the white part a bit. If that piece can't be changed, you could also add a 3D-printed clip to go around the black piece. I would add extrusions to where the holes are for the screws.

this will obviously not be as strong as the screw but it would hold them in place

not sure which pieces are you talking about, if you talking about the two white ones, then how about T-slot drop down from the top down or from the side depending on how you removing the parts from this fixture, perhaps bit more details could help

I need to disconnect and connect two white parts from the black ones, the black parts are fixed. And thank you for your answers.