The Renogy DC-DC requires a sense line to detect engine running. That's an extra wire (18 AWg or so) from the Hawk to the truck. The upside is that the 10 AWG factory wire from the Hawk to the truck will handle the 44 A (this is DC and the insulation is rated for the higher current - see rando's posts in https://www.wanderth...om-the-factory/
The Victron DC-DC 30 A can sense engine running without an extra wire. However, with the 10 AWG, it often cycles on and off every few seconds my experience and see pawleyk post in the same link above.
The solution is to upgrade the wiring from the Hawk to the truck to 8 AWG (works for me) or 6 AWG wire. Or, like the Renogy DC-DC, run an extra wire to sense engine running. The Victron offers both "smart" sense and wired sense.
In either case, you will need to replace the thermal breakers with a 40 A or 50 A breaker. There is one near the truck battery and one in the Hawk, near the battery isolator.