Hello, I realise that I am a few month late, but I have found the culprit. Hopefully it will be still useful to some of you. Basically to have an option of selecting 5 GHz, you have to have your hotspot in Wi-Fi Hotspot modem, and not in Wi-Fi Sharing mode. You can read the difference here: https://medium.com/@ximplifyit/wifi-hotspot-vs-wifi-sharing-configuring-lg-v20-4a14f67db23f To do that, make sure that the box bottom box above the list of connected devices is unchecked. Hope it helps.
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