I am partial to TP-Link Kasa switches. One of my neighbors uses two of them for the pool lighting and they have very good wifi range. It will be what I use at completion. As for finding the neutral.... It's the white wire always on a 120V circuit. The hot is usually black or red but neutral is always white.
By the way I also use Sengled zigbee lights with their cheapo hub for smart bulbs. The TP-Link switches are more reliable to respond but both are fine.
I have a Kasa in the bathroom and emailed them about using it for a pool light..They said as long as it's in a water tight box shouldn't have any issues