Not the best time with the GPU shortages going on. I'd run out and grab a 1050 TI or RX 560 4GB immediately. Scour the used market for 1060s, better option if you can get one. Before you decide on anything else buy a GPU. For a $500 budget you'll want to stay below 175.
Figure a Ryzen 5 CPU is your best bet, maybe an Intel dualcore for Total War? Don't know how it's optimized. Check reviews. You want a B350 board if Ryzen and B250/H270 if Intel. CPU budget $150ish. Good boards start about $70
Splurge for 16GB RAM if you can, I've had games demand >8 even on medium. Sometimes higher speed RAM is the same price, brand matters little. Though I've never had luck buying G.Skill
Seagate SSHD Hybrid drive, people overlook these. Surprisingly effective. Full on solid state is out if your budget.
Read PSU reviews to find the good cheap models, 400w minimum here. Same deal with cases, there are good sub $50 choices. Read reviews. Buy on aesethics.
Look around for Windows10 keys. Can buy one for $15 or just run it unactivated.
Any questions?