Light switch relay

Headlight switch has 2 power supplies B1 and B2 for a reason. with only 1, a short at at tag lamp, trailer harness, anywhere, takes out ALL exterior lighting. So... separate circuits. Smaller fixtures and wiring fuse protected. Headlamps on a cycling circuit breaker.
headlight relays pretty much render the cycling circuit breaker in the headlight switch worthless so each circuit should have fuse. Short would stop, high beams or low beams but not both.
You could fuse B1 and B2 but keep those separate, not together on 1 fuse.