Help Understanding PCIE lanes and usages, it REALLY hurts my

MAG Z790 Tomahawk WIFI pcie 5 0 x16 slot 2 slots Lan Nahimic Audio 14+1+1 Power Phase Mainboard Supports 13th Gen & 12th Gen Intel Core Processors Supports DDR5 non-ECC, un- pcie x1 in x16 slot For $60 more, the Asus ROG Strix B650E-I Gaming WiFi offers PCIe support for the PCIe x16 slot and a PCIe enabled , along with a

pcie 30 in 40 slot Indeed, I know that an M2 slot divides the PCIE lines of the GPU by 2 (going from 5x16 to 5x8, as for the Z790 TOMAHAWK