OK, i have to ask: why not just use a wifi-enabled pi? Maybe with a repeater inside the garage?
In my house I had a tesla powerwall installed (yes I know, rich prick alert) the gatway has some shitty wifi that cant be disabled, and kneecaps the range of my house wifi, because it insists on using the same channel.
The back of the house can pick up the AP in the garden, the top front not so much. So a bunch of things are sporadic now.
tldr:
Wifi is fine until its not. Hardwiring for critical path stuff reduces a hard to diagnose mode of failure.
You could also tape some antistatic bags together around the power wall box to act as a faraday cage, and throw in a Pi acting as a wifi-to-Ethernet bridge into the box or inside the f cage to get a wired signal out, if the interference is really that bad.