I need help with streaming/gaming pc setup

Hello guys i just made the account, i really hope u can give me some help. So i have a old pc with the following specs:
i5 4560k
gtx 960 4gb
8gb ram

And i want to buy new gaming/streaming pc with for gaming at 1440p on which i might do some minor editing etc... i already decided on buying the acer xz321q 32 inch 144hz .
So my question is should i keep this old pc and setup a dual streaming setup which i have no idea how to do. Or buy the best pc i can get for the money+ sell the old one so i can have more money to invest in the new pc and monitor.... Any advice is greatly appreciated. If i go with the 2 pc setup i might go with ryzen 3600 and not decided on gpu yet might wait for the new 5900 navi series. So anyhow i just want to know what is my best bet. And obviosly i want to keep it on the lower end on the budget as much as i can but at the same time if its worth spending more money for less headaches setting all up i will consider. Thanks again.
Also should i go with Nvec or X264 if u can give pros and cons would be also greatly appreciated and sry for the long post.