I dont know if this exists but there should be a way to like reset or degrade your stats. Cause if you are like me and screwed up and built your stats first now getting Rep is almost impossible.

must grow stat with targets if rep grind isnt over 

Reset is not needed , it feels travelling BACK..

You dint lose gain once you have gained..

Getting rep at higher stats isn't impossible, you just need to find a target.

Most of my faction mates with higher stats than me get way more rep if they attack someone than I do/did rep farming. Your target's level matters more than their stats since at most you would be able to gain 3x the rep if you get the full stat bonus, but the level of your opponent increases the rep you can gain even more.

I had 2 targets which gave me very similar rep, one of them gave me a 1.75x bonus and was level 29, the other one gave me a bit less rep, since although it gave me a full 3x bonus this target was only level 18.

As a reference point, at around 3k stats my targets gave me around 105-140 rep each