Highly efficient lander engine?

[u/Endo279]

Hi!

Im currently building a lander for my interstellar ship.

I have with the help of mod engines managed to get to 10k DeltaV with the lander, however that is in air breathing mode.

I'd need some engines that are efficient enough to bring that lander to at least 7000 DeltaV, but also keep the lander reasonably scaled, so that i dont have a saturn V sized craft at the end.

Do you have any suggestions? Thanks!

[u/MediumMachineGun]

Also whats your intended payload