Here's what I came up with quickly. $2.5K... really looking to slice some cost off this.
Where could I save costs? CPU is worth getting something high end I believe. I've got several HDD's so I want my tower to have storage slots and power supply for them.
I don't know if you saw, but I put together a quick DIY version for you in an earlier post, some bits of which you could re-use to bring the cost down.
As per the warning, you may need to update the BIOS to be compatible with Zen 2 processors, which usually requires an older processor to do so. I would pay the extra for a X570 board personally.
I would go for a higher tier CPU cooler, the Cooler Master ones are a bit basic. See the Noctua one I linked above for a robust air cooler.
Do you need RGB RAM? You can get much cheaper if not, see above. Do you also need 32GB? Most scenarios are fine with 16GB, unless you need to use memory-intensive apps. You could also add more later if needed.
Could you get away with a Ryzen 5 3600X (6c12t) opposed to the 7 3700X? I'm all for more power, but unless there is a appreciable difference for your use cases (this review has measurements for both processors), you can potentially save yourself $200 there.
Also, be aware that NewEgg is a US based outfit, so extra shipping + CGA doesn't apply etc