Hello. Looking for some advice for setting up RX rear derailleur. I recently built a bike with ltwoo rx groupset and I can't get it to shift at even somewhat acceptable level. Im using shimano 105 12sp cassette and a kmc chain with it. The shifting is ok from the middle of the block to the largest cog but on the smaller cogs, especially 4 smallest ones it's just total crap in both directions. You have to perform 2 shifts in order for chain to move. Sometmes it starts grinding with a single shift, sometimes not, sometimes it shifts(moving to larger cog seems a bit easier). I can get it to shift ok in one direction by adjusting the cable tension but then it stops working on a larger cogs. Derailleur hanger is straight. I have a full internal cable routing with probably doesn't make shifting better but i tried moving the cable by hand and theres barely any resistance in the housing. I tried using grx rx400 derailleur for test which should be compatible and it also shifted like crap. Would appreciate any suggestions,  I'm at the point of giving up and buying a 105 groupset instead.