Mine is similar. I have a 36v to 12v DC to DC converter for 12v LED lights, USB charger, and 12v socket. That converter is on a relay with the coil connected to the main key switch. I have a smaller 12v terminal strip under the dash so I just bring one 12v pair up to that strip and then power all of the 12v stuff from that point.
Meter same/similar to
this one.
My comment on turning the battery off at the BMS, if you have the BMS connections well insulated, after turning off the BMS, my battery pack can be disconnected from my terminal bar and the leads not be energized, which is nice.
This offering has the cells under compression and connected already, for a quick build.