Power supply and graphics card are a bit mismatched, also Gigabyte doesn't have the best reputation when it comes to power supplies in general, I'd try to stick with any 80+ gold rated power supply that's fully modular and 650W+ preferably from EVGA or Seasonic but other brands that have a longer history of producing power supplies could be good too, Gigabyte is just kind of the budget brand when it comes to these parts and it shows in the tech they use.
As for the GPU, I'd go two steps higher and get the: XFX Speedster SWFT 309 Radeon RX 6700 XT 12GB instead, Newegg sells it for 270 including shipping.
There's quite a difference in performance compared to the RX 6600 and I think the additional cost is worth it, especially considering this graphics card is sold NEW very close to its USED value, this is usually a pretty decent indicator of real value.
Additionally, you selected a PCIe 5.0 SSD but your motherboard doesn't have any PCIe 5.0 m.2 lanes, this means you'll be missing out on read and write speeds for your SSD, its not a massive problem as you can bring your SSD with you into a future build but if thats your intention, it might be worth going for a larger capacity from the get go.
Otherwise, see if there is a better value alternative for a PCIe 4.0 SSD with 1TB of storage capacity.
Its important to mention that when it comes to playing games, your PC should be centered around your graphics card, your graphics card does the heavy lifting so just try to keep that in mind.