Samsung Galaxy S20 plus 5G couldn't get stable 5G networks as compared to Qualcomm snapdragon chipset Samsung need to look into this concern and soon fix this one in the next update.
Of many possible causes two stand out. 1. Are you within range of a 5G cell tower. Note range is much shorter than for 4G. Load app called Aus Phone Towers, use hidden left menu to set for your isp and separately, 4G and 5G mapping, 2. Flawed cell tower settings. Google e.g. Telstra apn settings, search in phone for full phrase Access Point Name, and compare. If changing ensure current settings are written separately, 100% correct, spaces, caps, etc. in case you want to revert.
