Five days away from the problem will probably bring a fresh approach.
On the kernel rollback, I wouldn’t stay on 6.14 long term just for wifi. You’d be missing security patches and eventually you’ll hit the same wall when something else forces you forward. Fine as a short-term workaround while you sort out a proper fix.
Honestly, Realtek chipsets have a long history of being a pain on Linux. An Intel card like the AX200 or AX210 (on Amazon or eBay) is basically plug and play, well supported in mainline, and you stop having to care about this every few months. Cheap too.
Depends on what you’d prefer. Have a good trip mate!