Upgrading question

[Specter FXXK]

I`m upgrading my system from a Asus Prime A320M-K, To a MSI M7 AC (AMD Board) and from pc part picker, it says i need a 1 more EPS Power connector for the board, My current PSU (Corsair CX 550M) from the looks of it only has 1 EPS connector, need some recommendations for a PSU.

RAM side hm... need it to be at least 3000Mhz and 16GB (need it for FL studio since it favors fast ram, gaming, productivity like Photoshop/premiere (has to be cheap RAM, these ram prices are stupid)

Need a GPU Nvidia preferably (cheap not like a 1050ti but like a 1060 or AMD equivalent to a 1060

 and if you want to help me more, need a cheap case that can be upgraded (must have glass window lel) and at least 2-4 Front USB Ports)

I have only like 300-500$ on me from last year that I couldn't get my 1070ti due to Crypto mining back then so yeah...

if you can keep it between 400$ and if necessary 500$ not more than 550$.