No signal at boot

[BreBo]

To install kext, do I need to add them in Efi / clover / kext / other?

If you use MultiBeast to install Network and Audio, the kexts are installed in /Library/Extensions
Add FakeSMC.kext and RealtekRTL8111.kext to EFI/CLOVER/kext/Other so you can boot into Recovery Mode.

why the connection work when I boot macos from usb?

Did you already do a post installation with MultiBeast?