@JimDaniels So simple. That's what I was hoping to find in the configuration menu in the SIM card section. Something like "auto reconnect when traffic drops to 0" (with unlocked PIN) I'm owner of...

Same issue here, Archer MR400 V3, I' m so frustrated as I have to travel 300kms away in order to reset router and make it work, but reset works like for 10mins to 3-4 hours max so I have to reset it...