I am hardwired!
I bought the power supply from TRC Electronics ($18 total) along with some wire from Amazon.
The power supply features an AC Input (Hot/Neutral), ground, and DC output (±). By default it outputs 3.3V but it has a small rotary for voltage adjustments, I tuned mine down to 3.2V (same as my battery).
The power supply is slightly larger than I anticipated. (Comparison with AA battery)
It was somewhat tedious getting it to fit inside, I wired the white wire to the neutral line (wire nut), and daisy chained the black wire to the hot wire on the switch. The ground cable went to the unused ground wire in the back. My light switch wasn’t connected to the ground since my box was metal. I also covered the screw terminals on the light switch with electric tape as a precautionary.
If you have a Z-Wave/Zigbee switch, this power supply will likely not fit as those are larger.
I also took this bracket out, they were two (top/bottom) took the bottom one out for more space.
Here are some more pics:
I taped the battery terminals as I didn’t want to solder.
Seems to work perfectly so far! App reports 100% battery.