You're right about microwaves messing with Wi-Fi, it's crazy. I once had my router next to the microwave and my video calls would drop every time someone heated up leftovers. Moving it to the other side of the kitchen fixed everything (after a lot of frustrating buffering).
Your microwave might be the main problem since they're terrible for signals. I had to move mine three feet to the right once. Was that the appliance causing your issue?
Moving appliances three feet is such a weird fix but it works. It reminds me of when my old cordless phone would pick up my neighbor's baby monitor. You'd just hear static and then a baby crying out of nowhere, totally creepy. All these dumb signals bouncing around. What was the weirdest signal interference you ever got?