Delaney I know it's likely not the router as other devices are working, but have you tried restarting the router and 'forgetting' the WiFi network and reconnecting from scratch.
Also, do you have internet connectivity checks turned on? It won't fix your problem but it may just help by letting you know if the network you're connected to has issues, according to those checks, which, unless I'm mistaken, go outside the VPN (and possibly use plain DNS even with private DNS turned on as well, though I can't remember if that is the case). It might just help you narrow down the issue, that's all.
EDIT: Ohh and have you made sure private DNS is off in the GOS settings and in the browser you're using? Just in case private DNS is causing your issue
EDIT 2: And of course, have you restarted your phone? :)