If your RokuTV/Roku device has ethernet capability, and you have not factory reset the device, you can connect via ethernet and use your mobile app to connect to the new network.
With the newer Roku Express 4k/4k+ you have ethernet capability if you have a compatible USB ethernet adapter laying around.
However, still easiest if you have a physical remote. Going to need a physical anyways if you ever find that you need to factory reset the Roku device since a remote is needed to setup/activate the Roku.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660x, Premiere+ 3921, Express 4k+ 3941