Correction; they will still repair them outside the first year, they’ll just charge you to do it (unless you get lucky). :)
I had my right joy-con’s sync button break, so it no longer works as a standalone single controller. Apparently another common point of failure, as the ribbon cable that connects to the main board is folded and sits on top the battery, where all the heating up must weaken it.
Ordered a replacement ribbon cable for $3 so I can try fix it.