RGB gets wrong values
It seems that maybe the FETS are not working properly with the 3.3v on their gate, could that be the problem? if so, how would you chose another FET or correct this one ?


Yes, this is the issue. You want an n channel mosfet with a VGS that is near or less than your control voltage. For a typical Arduino this is 5V or 3.3v. Otherwise the mosfet will not fully open.

Additionally make sure the Arduino ground is tied to the led strip ground.