You could also scrap the HDD altogether... and just make do with 500GB SSD, then add one when you have more money. granted you'll prob only be able to put like 4 or 5 modern games but still, performance will be constant.
I'd say 1080 @ 144hz or you could go 1440 @ 144hz, with a fast response time. but I'd avoid 4k monitors right now. Since this build wont game in 4k to well and they will be
super expensive if you go for a 4k @ 144hz monitor. and one with AMD freesync. you honestly could do fine with a 1080 @ 60hz too if you don't want to play anything over 60 FPS (even older games) though not sure if 60hz monitors have freesync
I went with this one and works well for me. (24" 1080 @ 144hz and Curved) i had to change some of the color settings i didnt like the presets. You can find others on sale for cheaper it just may not be curved.
you could find a cheaper Power supply, and maybe slightly cheaper ram and maybe a cheaper mother board. Though I wouldn’t recommend even looking if anything it wont be that much cheaper total, unless something is on sale somewhere, and you'd get lower quality parts that could fail making you spend even more... after mail in rebates they are decent prices anyway.
If your looking to cut costs consider getting a 1TB HDD and a 250 GB SSD instead of a 2TB and a 500GB. Yes less space but it wont affect performance and with a 250GB SSD you can still can put one or 2 of your favorite games on it. Then when you have more money to spend you can upgrade it. You can also even go lower and get a 1TB HDD and a 120GB SSD. the SSD would only be for the OS and you core programs though there wont be room for games
Also try looking at slickdeals.com people post sales there all the time. may be able to find some stuff here or an equivalent for cheaper.