Hello there. I've got enough money for a $600 gaming PC build (including peripherals and overall taxes) that wont overheat too much and will have good connectivity for multiplayer online. I also already set aside an additional $100 for the windows operating system. I am not great at picking parts since this will be my first build and was hoping to receive some input from you guys. Hopefully it could be mid- atx sized but that doesn't matter as much.
Few days ago I bought a Windows 10 Pro key from ebay for $2.37, so I would suggest you spend at most $5 for windows(plenty of offers for less than $5 on ebay, just buy from reputable sellers if you are worried) and add the rest to the budget.
King Dranzer's Ryzen 5 2600 based build is pretty decent for your budget.
I have a Ryzen 5 2600 rig myself (see my signature for my full specs) and it performs extremely well for 1080p/60 Hz gaming.
Personally I would recommend that you try to save up another $30- 50 or so and get a good mid level B450 ATX motherboard like my Asus ROG B450-F Gaming.
That way you can upgrade your CPU and GPU in a few years without worrying about whether your motherboard can handle it.
I would also get a good 650W PSU for the same reason.
The motherboard and PSU are the foundation of your PC. So if they are good quality components, you won't have to replace them when you want to upgrade later.