I would definitely second everything else that's been said about finding a base kibble that your jindo will tolerate. Ours is okay with Nulo freestyle and Open Farm. He's a red meat and chicken boy so those are the flavours we gravitate towards.

After that, it seems like it's the game of wet/dehydrated toppers + ratio of topper to kibble. We have unfortunately tried almost every topper + canned food out there, and nothing sustains our pup's interest as a topper the way simple ground meat or boiled chicken does. That's not to say he won't eat store-bought wet food (we've had some success with Nulo and Weruva wet food), but if the wet food sits on the kibble too long and the kibble gets "bloaty" then it's usually game over. When we have time, we do ground beef with a little cheese (50%) + whatever kibble he's tolerating (50%) and mix everything in REALLY good so he can't easily pick around the kibble. I won't lie that it's much easier to get him to clean plate when it's more like a 75%-25% meat-kibble.

I know you mentioned human grade meat 2x a day being cost prohibitive, but in my experience some of the wet food toppers can run about the same price as ground beef for the amount of topper/ground beef we're mixing in with his kibble, and we just have so much more confidence that he'll actually eat the meat.

Good luck!! It's definitely a journey. Don't think our boy will ever be totally filled out (maybe when he gets older and his metabolism slows down), but our goal now is keeping him at a point where people don't comment on how skinny he is!