I never got confirmation that it was related to 3G sunsetting, but I had this issue when I stopped driving my 2017 Outback regularly at the beginning of the pan

I never got confirmation that it was related to 3G sunsetting, but I had this issue when I stopped driving my 2017 Outback regularly at the beginning of the pandemic. The first trip to the dealership resulted in a "software update" that didn't seem to do anything. On the next visit, with photos I'd taken of my voltmeter showing parasitic drain, they replaced the DCM. I think they charged around $800 for that and a new battery since the original was toast from too many total discharges. I reached out to Subaru of America and as a one-time "goodwill gesture," they refunded me for the cost of the DCM.