Hi, I am still having problems with loss of data after coming off wi-fi. This is the FE 5g and only got it just after Christmas. Not impressed with it and this appears to be a bad advert for Samsung. Never had issues like this before on previous Samsungs. I still have it in mind to return the phone and get my money back. Currently to me this os the worst purchase that I have made. Can only get better....I hope!
You could try clearing the network settings on your phone. If it's still persists I would call your provider and have them try to reset things on their end