Proper installation of a supply line escutcheon
Use copper stub outs for pex.  Like this:
https://www.amazon.com/Sharkbite-25094A-Copper-Elbow-Bracket/dp/B016Q4OAKY
It is very difficult to finish pex coming out of a wall nicely.
https://www.youtube.com/watch?v=IVD-ZMC2jA0