Oh gosh the last few days have been a thing.
But hey, I’m moved in. I don’t have (proper) Internet yet, but that’s coming in tomorrow.
In the meantime, I needed to set up my new Roomba, and it can only do its full setup1 via a phone app, which requires an Internet connection and local wifi to work. Fortunately, I found my router, and I have my desktop computer set up, and macOS makes it easy to share an Internet connection from one interface to another…
… so I enabled my phone’s hotspot, connected my desktop’s wifi to the phone, shared my desktop’s wifi to ethernet, plugged the ethernet into the uplink port on my router, and then connected my phone back to the router.
Somehow it all works! It’s going through like three layers of NAT and the phone ends up doing double-duty in the most roundabout stop-hitting-yourself way, but now my Roomba is set to wake everyone up at 9 AM, probably scaring the crap out of my cats who have never seen a Roomba in their lives.