budget gaming/editing pc

Hi friends, i'm looking for good pc for 4k video editing without any lag. currently i'm using macbook air 2014 model . i'm using davinci resolve for editing 4k footages. i'm planning to upgrade . which will be better for my requirement : macbookair (retina) 2019 model or imac 21.5 (retina 4k)...

So I want a budget 750$ gaming/editing pc that is capable to show 144fps for my 144hz monitor here is what I was thinking about but I wanna see if I could get a better one: https://pcpartpicker.com/list/D9xVNQ Ps: 16gb of ram is neccessary for me