I've had my Samsung Fold 3 for only a few months and about 2 months ago it starting have a problem remaining connected to wifi. To use any services requiring wifi or mobile data - e.g. whatsapp - the phone has to be restarted. It connects to wifi and then remains connected for about 2 minutes after which it no longer works with wifi even though when one goes to Settings, the wifi is still connected. Any time i want to check my whatsapp messages, i need to restart the phone. My whatsapp has not backed up in a long time because there is insufficient connection time to wifi to do a backup.
Is there a check or settings adjustment i can do? Bought the phone in the US but working out of country and have been told I need to take the phone back to the US to sort out the problem or apply the warranty.
Try resetting network settings. Go to settings and search for "reset". It will lead you to reset network settings. It is also possible that your phone received a software update(2 months ago) and it has caused some issues.
Maybe wiping cache partition will help you. Search online for it.