Correct place for this would most likely be the discussion on the Patreon video you are referring to.
I feel like it wouldn't be impossible to use the shield to rewire the hand x-bow if it had a hook attached to it. A bolt feeder of some kind could be used to drop the bolt in to its place. This would sill require refilling the feeder once per turn but it could be done as a free action.
I know it's stretching the rules but i feel like rule of Cool vs RAW can be applied here to make it possible. JP essentially gains +2 AC but his character is gimped by the fact that he can't use Heavy Armor. Not like the build is extremely powerful anyways. At their current level Ranger could dish out more damage constantly while spending next to no resources if the same build was applied to that class. (More damage due Colossus Slayer and Hunter's Mark working really well with multiple hits. Level 11 Fighter gets more attacks per turn but Rangers gian Volley)
The next feat in line is Lucky. I feel like one should be able to use hand x-bow just fine with a shield when you can make a disadvantage in to an super advantage. When you really need to hit just close your eyes to gain disadvantage to be able to roll three dice and select the highest. Feats are silly that way.