Any system ready for W10 or 11 will do, most of NTLite's work is disk bound (extracting files, copying, writing to WIM or ISO).
Disk speed (HDD vs SSD) is more important than extra memory, but a faster CPU obviously shortens the wait. NTLite will run inside a small VM, if you don't care about the wait times. Disabling real-time virus protection speeds up NTLite a lot, since the system isn't checking every file.