No need to make this complicated, just tedious
Use small pieces of paper tape or mesh, 4"-8" will do and go around the window. You can also cut the paper or mesh tape pieces with a drywall knife or scissors to accommodate the curve.
All just takes a bit more time.
I bought some expensive flexible tape years a go on a job, never bought it again.

Thank you for the recommendations,  I need the trim that goes against the sheetrock and the window not the outside corner. I could use paper tape but I like tear-away trim because you can tape tight to the window then tear the strip to make a clean reveal. I can't seem to find a segmented tear away like that corner bead.

Are you looking for something like this?