Battle boss brand or project jhin

keep both :D while eventually buying them off of orange essence. since obviously you dont play them so you dont need to sell/buy them yet

I'd just take a moment to evaluate what you're really interested in. If you haven't already, take a look at each champ a bit more in depth and get whichever one that goes for the champion you'd find yourself playing more often. If you can't come to a conclusion with that and don't really play either much as it is, holding onto both and waiting for more essence doesn't seem like a terrible option.

I have both. I think Project Jhin is a much better skin. But IMO keep them both.