There is ample volts at the battery- install relays and things should brighten things up. You are loosing it in the harness, light switch and connectors along the way. Stock low beams are 35w/35 w and the high beam is 50w. Your halogen high beam is probably 50w?
Don't skimp on the relays, get a good brand like Bosch, and 40A like 0332019157. You want short runs from the battery to relays to lights with heavy gauge wire, something like the attached
HEADLIGHTS.pdf