How can I Automate for selected apps to only use cellular data and not Wi-Fi... and vise versa?

I tried doing it myself (On Automate) but it's a bit too advanced. Can I get your help? Also, I think Android overriding data connection when wifi is on might have to be factored in. I could use Afwall (and Netguard?) to control what connection they use but if the wifi is on, then the app won't be able to use data. For example, on Afwall, I have app x restricted from using Wi-Fi and enabled for it to only us data. But if both WiFi and data connections are on, then the app gets no connection. But if I turn Wi-Fi off, then it will get connected. Turn Wi-Fi back on and no connection again. How do I get around this? Android 7 | Rooted