I have lots of curtain rods in my plaster-walled house. Do you not want to drill into the plaster, or do you think it isn’t possible for heavy curtains?

Can you hang the curtains from the ceiling?

You can drill into plaster walls using the correct method and hardware.

You would also need the correct rod and brackets to hang from the ceiling.

Not sure what you mean by brackets that sit behind the frame.

Don't know of any heavy duty tension rods.

No Idea if these work.

https://kwikhang.com/products/single-bracket?variant=1595693072407&gclid=EAIaIQobChMIu8yvlPK77gIVT_DACh0S_QlYEAQYASABEgLFefD_BwE

Not sure I understand exactly what you are looking for, but the brackets that sit on the frame- so you mean this? ( I believe it was a Shark Tank early on product).KWIK HANG . I bought a set and it really is quite simple. They basically rest on the frame, and gravity keeps them secure.

They will only work though, if you are hanging the curtains level with the window frame. At least for my understanding.

They do work, and they are secure, and they require no drilling or anything.

why would i want to hang from ceiling as opposed to a few inches above the window frame?

also, these are the brackets i'm referencing:

https://kwikhang.com/

Because the material on the ceiling may be better to drill into than the walls - all depends on what material your walls and ceilings are.