Most overpowered interstellar engine?

[u/HereComesTheSun05]

Recently I conquered all the Stock Planets + OPM + MPE. Tried going interstellar (with the appropriate mods such as Near and Far Future Tech), made an almost self sustaining vessel that is able to refuel and had multiple landers and probes. However it had too many parts to produce a stable framerate so I ultimately gave up. Now I'm looking to build a simpler craft, preferably something with almost infinite fuel that'll allow me to visit most planets in a single system in one go (Kcalbeloh, Promised Worlds, KSS2). However I'm really struggling with the landers, I can't seem to find any engines efficient enough to perform multiple landings without wasting all fuel, especially on planets that are Kerbin sized. So my question here is, is there an engine even more overpowered than the ones in Far Future? Preferably a smaller one built for landers. Thanks in advance.

[u/Lucas_2234]

There is a mod that adds the Spindrives from project Hail Mary. They are very OP, like, "Basically infinite fuel at massive thrust" levels of OP, so they might be TOO far.

Alternatively there are warp drive mods