I may be wrong about this, but with both monitors on can you drag it back to the one you want it on? Then it should come up that way when you open it again. At least windoze works that way when I've used an external monitor with my laptop.

Bruce


Macbook Pro 2018
2.6 GHz 6-core Intel Core i7, 16 GB RAM
OS Monterey
BIAB for Mac 2022