Drives

The STRIX Z690 comes with four M.2 slots for PCIe 4.0 x4 NVMe drives, the fastest "disk replacement" available nowadays. These slots can carry M.2s in "length" 2242, 2260 and 2280, and two slots also support the extra long 22110: this was once needed for large storage capacities, but lately the fastest M.2 2TGb recommended to me by flight simulation fans come all in length 2280.
M.2 drives come in different maximum read speeds, e.g. 3300, 5000 and 7300 Mb/s. For Flight Simulator 2020 I was recommended the highest speed, as it often reads high volumes of data. I got and tested Western Digital M.2s with specs stating a maximum read speed 7300 MB/s, and my tested average/sustained read speed was the still impressive 5250 MB/s.

This said, most games do not need such a speed and you can settle for slower and more affordable M.2 strips. Anyway, bear in mind that you will have a huge increment in speed (up to almost 10 times) compared with SATA SSDs, which are mostly rated for maximum read speeds around 550MB/s.