I have a similar budget, although without a GPU factored in since Im waiting for Elder Scrolls 6 recommended specs AND prices to drop.
Here's what I've been looking at:
Asus ROG Strix B450-f (for the excellent onboard sound mainly, everything else seems pretty good and comparable to others)
AMD Ryzen 5 2600x (seems a great fit price/performance)
Corsair Vengeance LPX 16GB (great price right now at $95)
ADATA XPG SX8200 Pro 1TV M.2 2280 SSD (reviews on this are outstanding)
APEVIA X-Dreamer 4 ATX Mid Tower gaming case (comes with 5 fans installed, temp display, seems roomy, looks nice with the green)
Acer Nitro VG271 27" 1080 IPS with Freesync 144hz (can't find a 1440p model with the same specs/price)
AmazonBasics Displayport to displayport cable 6 feet (I believe this is the right cable, not sure if one comes with the monitor)
Optical Audio Cable IVanky (I have a Z-5500 that will operate really well with the new mobo and this cable, I"m using colored wires on my current and it's very low volume used to have optical but I thought my current onboard sound couldn't use it after the SB X-TI Titanium card I used to have failed and I procrastinated about getting a replacement and stupidly put up with substandard sound for year)
Updating in anticipation for Elder Scrolls 6. Plus a few others I have now that would benefit. I've been shopping for weeks and having trouble hitting the BUY button. Lot of money to spend only to find I screwed up something or even maybe I should have waited. Specific reason for upgrading...