My new nextion 2,8 touch should be connected with a 3,3V Arduino.
The nextion wants to be powered wit 5V.
But what level do the Rx and Tx pins have/need?
Do I need a 5V level, or can I connect them directly to the pins of a 3,3V arduino
nope, they are 3.3 volt - I am using one with a ESP8266.
One thing to note - If you power the display and the arduino sepratly is to have a common ground