Ring Video Doorbell Pro disconnecting after 5 years no problems

Hi, After nearly five years of no issues, my doorbell suddenly went offline about a week ago (doorbell software update?). I've tried resetting it, and the router, but to no avail. Occasionally, it will re-connect itself, then drop out again. Totally unreliable. I have a dual-band modem, but can't separate out the bands to separate SSIDs. I know that the doorbell won't work on my 5GHz band as the available channels are all under 100, so I'm wondering if the doorbell is now trying to connect to 5GHz? There seems to be no point in getting another Ring device if this problem may re-occur. Such a shame as I really don't want to move to another system. Any suggestions would be much appreciated.