Hi. Couple of things, new hardware is releasing and the CPU and GPU you have chosen will be replaced very soon.
5th November sees the release of Ryzen 5000 series processors, and 18th November AMD releases the Radeon 6800XT, which is in the ball park of the price for your GPU. So if you can, wait until they are released and hopefully Nvidia sorts out supply of the 3070 in the meantime. Because it should be priced at $500 and is significantly faster then the 5700XT.
Other then that I'd suggest getting a single 1TB SSD. You'll have less space overall, but you really dont want to be running games off a hard drive in 2020 IMO. Its better to add more storage later if you need more. A quick look shows the 1TB Crucial P1 NVME drive on sale at newegg for $134 at the moment. That Crucial 250GB drive you selected is way overpriced for some reason.
Otherwise cases are a matter of taste for the most part, and you picked decent RAM and a very good PSU. I'm not too up on B550 motherboards, but I think the one you picked is fine. You can probably go cheaper if you need to save a bit.
Just a final tip if you didnt know, occasionally if you pick RAM that is not on your motherboards QVL list it can cause problems. Not always but its worth avoiding the risk IMO. The list can be found on the manufacturers support web page for the mobo your looking at.
Thank you kindly for the reply. I think I can wait, I just wonder how availability will be. ( especially new amd gpu).
I'll look into ram compatibility as well as switching up ssd.
Again, much appreciated!