Thanks for your answers.
I think I am not expert enough to delid a CPU: it's my first build so I would prefer to avoid this operation.
The RAMs are the Trident Z and I could also buy a 750W Corsair RMi Psu.
I think I won't do OC in the firts period of use, so I could buy the Noctua air cooler now and then switch to a liquid cooler from Corsair or Cooler Master, like the H100i.
I have to possiblity to pay the MSI or an Asus TUF Z370 Pro motherboards less than normal, but the choice is limited to these two Mobo.
The 144hz 1080p monitor would be the Samsung C27FG73 and the 1440p one would be the HP Omen 32''.
So the indecision would be on the cooler. I would prefer to save some money now and buy later a liquid cooler to overclock the Cpu.
Let me know what do you think.