I wasn't able to install regular curtain rail brackets in my house as there is steel-reinforced concrete above the window which I couldn't drill through, so I redesigned the curtain rail brackets I bought to be able to mount them on the ceiling. Made to fit at standard 28mm diameter curtain pole.

I also added a hole on the pole hook which can be used to attach the pole to the hook with a screw for some additional security, but for me it wasn't necessary as it was a good push fit and pops in nice and secure.

Base doesn't require supports, but I'd recommend printing the arm with supports and a brim/raft and with an infill that is strong vertically to support the weight.

I used an M5 50mm screw on the base to attach to the ceiling and 2x M3 15mm screw to attach the base to the arm, and the arm to the pole.