I have this exact type of window. We went with this side wall mount paired with a long Amazon basics curtain rod and center ceiling mounted support.

We also hung curtains with these little clips which make it much easier to pull back and forth.

I would hang the curtains from the very top, maybe two inches below the ceiling.

Are you trying to get a curtain across a room and not along a wall? And if so, would you able to use ceiling mounted curtain holders? They have a few different kinds.

Here’s one type, but may stop you from pulling the curtains all the way to one side.

Here’s another kind that’s more like what you see at a doctor office or hospital.

I used JB Weld to adhere it to the wall, then surrounded the entire end of the rod that was against the wall with water resistant Locktite. Then I fashioned 2 "braces" out of duct tape to hold it in place for the 24hr curing process.

...you just voided your security deposit. This is not how you install a shower curtain rod! This is not what either JB Weld OR locktite is for!

If the adjustable ones wouldn't "hold" you should've installed some ceiling mounted curtain hangers and put a rod of the appropriate size through that.