The Jobava - London systems has the same problem like other more unusual "system openings". It works good against some,  maybe a lot of defences, but there are some you just should not use it. But since chess writers usually want to present the reader an "easy to learn" repertoire, they use it anyway and ignore the problems.

I am working on a repertoire with the Jobava - London for some time and I found out that it is a great weapon, if you mix things up.

In some main lines, you best use the original London System. In others you use Jobava Nc3 - Systems instead auf the London c3-Pawn.

To be able to do that, I play Bf4 before Nc3, except 1.d4 e6 2.Nc3 or 1.d4 f5 2.Nc3.

And finally: Almost every time Black chooses an early Bf5 - system or Bf5 remains possible, I delay Nc3 or c3 as long as possible. As soon as Bf5 is played, I play c4, often followed by Qb3, which is much better than the original Jobava-London against Bf5-Lines

I play those lines a bit with White. Objectively, I would say you just have to accept that they're nothing special. The main objective is to unbalance the game and steer towards an unusual position that you might have greater familiarity with despite the verdict of theory.

The problem I find is that I do get a sinking feeling that I'm playing for positional cheapos, and if Black knows what he's doing, play can get quite narrow and there isn't a huge amount to look forward to.