I'd have a hard time choosing EK J over LH F. Even though the full LH F ground experience isn't back to what it normally is, the F experience on LH is all around just better and more personal than EK J.

What it really boils down to is whether it's worth an extra €1500. I can't really answer that question for the OP but if it were me, I'd say I'd probably go for the F option at that price difference.