@raya2 I have to ask because I don’t get your setup.
– Windows is you spacedesk server
– Android is your client, where you wanna extent/mirror your windows screen?
If so, you can use USB tethering on your Android to get connected to spacedesk server.
To not tether your internet from Android but using still your Windows machine wifi, change the IP4 settings (metric) as describe here, 2nd post.