Can you use 4G on Samsung S21?

Step 1: Go to Settings > Connections. Step 2: Tap on Mobile Networks. Step 3: Tap on Network Mode. Step 4: Select LTE/3G/2G (Auto), LTE/CDMA, or one of the other 4G/LTE options to prevent the phone from using 5G.

The Samsung Galaxy S21 Ultra has now been configured for use of 4G networks .