Other forum posters have reported that some smartphones cannot tether to some routers because OpenWRT drivers may be missing for the smartphone hardware:
Tethering testing with various android phones, an iPhone and various GLiNet routers.
GL-AX1800 Flint * firmware version 3.208 {QSDK11 (openwrt 15.05.1)}
iPhone SE (2020), iOS 15.1 - Detected and connects to internet
Nexus 6P, Android 8.1 - Detected and connects to internet
Oneplus 8 Pro, Android 11 - Not detected
Oneplus 6T, Android 11 - Not detected
GL-S1300 Convexa-S * firmware version 3.211 {QSDK11 (openwrt 15.05.1)}
iPhone SE (2020), iOS 15.1 - Detected and connects to internet
Nex…