Your washing machine could be sending 3.7 GB of data a day — LG washing machine owner disconnected his device from Wi-Fi after noticing excessive outgoing daily data traffic
This sounds like some kind of DDOS attack like the ones that involved connected light bulbs. Malware gets into the light bulb or washing machine and repurposes the infected device to flood targeted servers:
I have an LG washer and dryer on my IoT VLAN and funneled through a pi hole. I've been pleasantly surprised at how quiet and well behaved they are on my network. Hardly ever phone home and only connect to one or two domains. Something is seriously wrong with his dudes washer.
The most noisy devices on my network are my smart TVs. The last time I bothered to look, it wasn’t even close to comparable.
My phone is my most used device. It had something in the ballpark of 800 blocked requests in a day, after an entire day of doomscrolling and heavy use. It was the third most blocked device on my network, behind both of my smart TVs. The “better” TV had ~2400 blocked requests in that same day. The worse one had nearly 3000.
Crypto mining would be symmetrical up/down though. This is only a small amount of data downloaded, and a huge amount uploaded. That looks more like a botnet attack, where an attacker hacked the machine and pointed it at a target, then just left it to run.