Sometimes they're tricky to get threaded right, maybe you just have it off angle everytime you try it in that frame.
Does the frame have removable derailer hanger by any chance? Maybe it'll be easier to thread hanger to the tensioner bold.
I will fiddle with more angles to get it in.
it doesnt have one of those hangers.
I also have a theory. It is an inexpensive department store bike. Most likely of inferior quality.
i'm thinking maybe that one off factory in the middle of china decided to make that hole 1mm bigger/smaller to make my life harder. Oy
Edit: i spent some time doing a wiggle/screw technique. After vigerous wiggling and screwing its in! Thanks