You don't need to edit it in 4K.
If you are using Premiere Pro, you need to get Adobe media encoder and in the ingest settings of Premiere Pro set it to produce proxies. I use 1280x720 H.264. It will take a while to process it, then work with the proxies. The proxy copy is the same as the 4K footage. Work with that, and when you render it will use the 4K footage.
You can set the level of the proxy even lower depending on your hardware. That way you can edit the footage on less-than-top-of-the-range hardware. When you come to render it, just let it render to whatever quality you require. It might take a while, so you may need to leave it on overnight!
I built my PC before I started wanting to edit 4K. It's a Ryzen 3 1200 with 16Gb RAM. The graphics card I needed to put in to make it work is an Nvidia GEforce gtx 1050 Ti. Not the most expensive, but this setup works well for me using the proxies to edit.