@ethonkent-
If you have a single-band Roku that only sees the 2.4 GHz WiFi band (primarily non-4K Roku Express/Express+ with model numbers below 3940 and Premiere/Premiere+ with model numbers below 4620), be sure your phone hotspot is set to use the 2.4 GHz WiFi band, not the 5 GHz band.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X