What glue to hold wooden batten to ceiling for window blind

Today I attempted to put up a window blind, fixing it to the ceiling (there is no option to drill into the window frame)

My metal/pipe detector has ‘pinged’ where I want to drill the holes into the ceiling. I’m guessing an RSJ.

I drilled a hole any way, and it’s only 1cm deep (before hitting the RSJ)! As such, I think my only option is to glue a wooden batten where the ceiling meets the wall (inside the window recess). I can then attach the blind to the wooden batten.

My question is concerning how to affix the batten to the ceiling. With only 1cm depth, I’m not sure raw plugs are going to work, and it’s really unclear if glue will strong enough.

Is there a glue that is designed for this purpose, or is my approach flawed?