Still having problem with dvs bpm sync- old but still existing problem

I seeked out for help here once but the answers werent satisfying. I tried to work my around the mentioned problem but somehow that is not the real deal.

To begin with my setup: 2 Pioneer PLX-1000 turntables + Pionner DJM-250MK2.

I use dvs, which means I use control vinyl, 2 of them, recommened for rekordbox usage.

I try to DJ with Drum and Bass which means like bpm around 170-175. But that doesnt really matter since you find a ton of people with a different music styles struggling with the same problem.

The problem: Using the Rel mode on bpm-sync pretty much never works. People told me its like the flutter of the vinyl and stuff. I could accept this explenation... on absolute mode but not on this one. You are basically telling me both are the same modes dealing with the same problem but on absolute you have to put the needle on the beginning. That doesnt seem like the correct explenation.

I just stopped my session cause even tough bpm sync is on I have a difference of round about 2,0 bpm! That is definitely not the problem of my setup since I also use normal dnb vinyls. My setup was done correctly, I calibrated on the software as well and looked at every possible setting. At this point I am certain to say its not my fault its the software.

Since I dont got the money for constantly buying new vinyl I switched to control vinyl. I also liked the idea since im working full time, that it is nice to just let the software do a little bit of syncing beats so I can relax and focus more on music and easy transtitions than dj-skill. Still have my vinyls for that. But right now the software is giving me more work than If i was going back to 100% digitalfree.

So my question was, and still is: How do I get rekordbox to stop f'ing up bpm sync?

Sorry for bad english. Not native