Some general advice: cut as many expenses as you can and get a higher end GPU if your only performance demanding activitity will be gaming. You can get a 4070 at this PC budget if you make some cuts elsewhere. Although I understand if you prefer a fancy case - and motherboard with all the ports, I'd personally move $150 from those two towards your GPU.

Regardless of if you do or not, that PSU looks sketchy. I see some Reddit threads saying that, while it's electrically good, the fan is super loud. Always get a PSU that went through rigorous testing and the wider enthousiast community backs as reliable in every way: power quality, reliability, warranty honor. Most gold rated Seasonics and Corsairs will do fine in those categories. You don't need more than 600W for a build in this range, so you can go for a cheaper wattage option.

While AM4 is still a very cost-effective platform, I don't get why you want a 5700G when you're not going to use the iGPU. The 5700X supports PCIe 4 and has more cache.

The Ryzen 7 5700G only supports PCIe 3.0. Your GPU is PCIe 4.0 so you may lose some frames as the connection will be downgraded to PCIe 3.0. Same for your SSD, it will be downgraded to a PCIe 3.0 connection.

I have a 6750 XT, although it's the Asus Dual version. Goes hard. I use it for 1440p gaming and it's performing well. (Has some coil whine in certain scenarios, though.)

Finally, unless you are really set on the ITX form factor it may be worth going to micro ATX. It will be cheaper and you'll get better cooling in a larger case.

I haven't made one since 2016 and about to create one in the next few months now that costs have lowered a bit. I have been following for a few years and the only suggestion I can make based off what I am doing is go AMD. I have been an intel person prior and this will be my first AMD build but from everything I see AMD is killing it lately.

For a $1300 build you should be on AM5 playing at 1440p with no issues.

https://pcpartpicker.com/list/xkBdmD

Motherboard: Pretty much one of the cheapest options with wifi.

Cheaper and still very good storage more than enough of your needs.

GPU general rule of thumb is to go for the cheapest AIB (version), its black/silver so if you want can get pure black for 10 dollars more.

Case in general is personal preference but you choose a way too expensive one for no reason, this one is a smol like the matx you chose and really nice in my opinion

PSU is pretty much one of the cheapest high ends, you can save 20 dollars or so by getting a C or B rated.