CPU Upgrade - Intel or AMD?

Dec 1, 2018
When I first built my PC I got an i5 6500, a Z170 LGA 1151 mobo, and a GTX 1060. Recently I've been considering upgrading my CPU, as it has become a noticeable bottleneck as of late since I bought a 144hz monitor. Recently I've noticed that while playing Destiny 2 or Monster Hunter World my CPU will be at near 80-90% load while my GPU is only at ~50%.

On to my question. I want to get a new CPU, and as I already have an Intel CPU I first looked to them. My first thought was the i5 7600k, however I've read that Z170 mobos need a BIOS update in order to use 7th gen Intel CPUs. As well, buying an i5 7600k is far from cheap, since I'm mainly looking for new hardware. The same is true for the i5 6600k, which I've also considered. Recently I thought to look at AMD. I'm not super familiar with the whole Ryzen lineup, but from what I've been looking at a Ryzen 5 1500X and an MSI - B450-A PRO ATX AM4 Motherboard would be cheaper than buying an i5 6600k for very similar performance.

Is there a better (and cheaper) Intel CPU that I'm not looking at or would a Ryzen CPU be a better choice for 1080p 144fps gaming?
i5 to an i5 won't make a worthwhile difference; you are running out of cores/threads.

The only worthwhile upgrade would be the i7 6700k or 7700k. BIOS update isn't a problem; do that with your current CPU, then sell the i5 on Ebay or something.

Switching to 8th/9th gen Intel would mean a new motherboard, as would Ryzen.

Ryzen, although it offers more cores/threads, isn't the best for 1080p gaming.