3600 or 3700x
3600 or 3700x
Check this build I'd examine: 3600 at https://pcpartpicker.com/list/BkWDTC and 3700x at https://pcpartpicker.com/list/myFtRk
Increasing clock speed and reducing voltage are techniques used to optimize performance and efficiency.
For pure gaming, opt for the 3600. Consider a TUF X570-PLUS instead of MSI's entry mid-tier boards—they're not worth it. You can find a good RM650x for what you'd pay for an RM750 (or cheaper), and 650W should suffice. You probably don't need a 750W unit. Assuming you already have the Vega 64, skip the upgrade unless you want it.
In gaming it might boost a few extra frames with the 3700x, otherwise it doesn't help for gaming.
Some RXMX power supplies include an additional cable not found on the motherboard, wouldn't that be inconvenient? This would likely affect PCPartPicker's item selection.