USB tether to router and then connect to the WiFi of the router no longer possible on recent Android versions?

I have somewhat of an unusual problem that wasn't a problem a few months ago, I had an Xperia X with Android 8 on it, and I used it to provide Internet (4G) for my devices using a router. It worked like so: 1. Connect to the router's USB 2. Configure router 3. Enable USB Tethering from the phone 4. Internet This is the usual method, of course. The thing is, I have a NAS attached to the router as well, and I used to enable the WiFi on my phone (with USB Tethering on), and sync/connect with the NAS without losing Internet connection. I upgraded to a Pixel and then a Samsung running Android 11, 12, and now 13, and there seems to be a change in what WiFi is. It's now related to the "Internet" instead of being a networking means that can be used to get files from a local server offline. Now because of this change, whenever I connect to the WiFi network of the router, I lose Internet (on Samsung) or simply the WiFi wouldn't even connect unless I disable the data (Pixel). Is there a solution to restore the old behavior or at least workaround it?