Car lighting help - Adding aftermarket LED Day time running lights

[gregzz4]

Ya that sounds like a plan using the markers and a new relay to power the new lights.
So try pulling the DRL fuse as you thought and see if the headlights still work properly in night mode.
I know back in the 90s Suzuki/GM had the 2 circuits connected together. If either the DRL or Headlamp fuse went out the Headlights were dim.