In that case, you should be able to add a “chainload” line to “/etc/grub.d/40_custom”. I can check my Win7 system to get the details, if you need that (it’s powered off at the moment).
Check the output of “os-prober” to see if it finds Windows.
Upgrading from 12.2 probably won’t help, because you will get the same “os-prober”.