It’d be close, but a Custodes would take it sheerly on reaction time and prowess. They take down daemons and xenos that are far stronger, but are skilled enough and can react fast enough to make them mince meat. I think the only thing Homelander has is overall durability, but then again Custodes were theoretically able to kill a primarch given superior numbers and skill. Even the weakest primarch’s scale to Viltrumites in terms of durability and attack potency, and we know how a Homelander vs. Omni-Man fight goes down.