So the note 20 ultra gives the proximity warning if the spen is far away or not in the phone for a prolonged period. I was taking off a case and took out my pen and left in on the table for a minute and then put it back into phone and it says it's disconnected and none of the features will pop up anymore. I did a restart as well. Idk if I have to reset completely.
Please try the suggestions made by @Jakebs . If the issue persists, please send us an error report. We apologize for the inconvenience and appreciate your contribution to the beta program.
One UI Beta Team.