I found here and in reddit that both the X1 and P1 series should use Idler Timing Pulley 20 Tooth Wheel Bore and a lot of the frequencies problems at high speed will be fixed but I haven’t found any information regarding why the printers doesn’t use them if they cost almost the same but by don’t doing it the users can incurs in a lot of other problems because it requires to disassemble almost the whole printer.