A discussion I had with someone previously when I was building my system (just started using the i9-9900k) was that due to EQ being configured for a single core per instance of EQ. you'll likely get more out of an AMD with more cores than a higher frequency with less cores CPU. The 2700x that William mentioned has an 8 core processor. The i9-9900k has 8 cores as well. Each has comparable frequencies, and each requires a specific cpu slot, which means different board choices. However the boards available for each have comparable layout's or options. Both appear to have like power consumption at 95w on the intel, and 105w for the amd.
The price of the 2700x is currently $248 on amazon.
The price of the 9900k is currently $489 on amazon.
I expect if EQ is the primary subject of the setup then the AMD is cheaper for like results. If expanding beyond EQ then it really depends on what you intend to play / do.
Intel info gathered from
https://www.intel.com/content/www/us/en/products/processors/core/i9-processors/i9-9900k.html
Amd info gathered from
https://www.amd.com/en/products/cpu/amd-ryzen-7-2700x
For benchmark comparison results you'll find i9-9900k shows it's ahead in 6th place, with the 2700x in 14th place. (at least for this specific site)
https://benchmarks.ul.com/compare/best-cpus
I just changed from a laptop, the difference is night and day for sure. I was using an i7 on my laptop with a 1060, ran too hot which caused throttling to occur to maintain a maximum temperature. Cleaning was a pain in the rear due to the nature of laptops in general. Typically requiring an annual in depth cleaning of the heat sink fins due to clogging of the fins if you failed to stay on top of things for keeping them clean. Specifically when running the system for a real long duration like I do.
I expect regardless of the route chosen, updating to a modern CPU would result in pleasing performance overall. However, if you're not already going over 50% on your system currently I wouldn't expect the gain you'll get to make much, if any, difference.
bottle necks for systems usually occurs for systems in the memory aspect, where you'll find yourself using more memory than you have. Before I ran 6 toons on 16gigs because I usually had a ton of other things running. I'm now using 32 gigs and my computer laughs at 6 accounts. So I expect if 6 toons is all you aspire to run, 16 gigs should handle it fine.
With all that said...you were asking about AMD Ryzen 5 3600 I didn't see a "k" version at the end of the number, but the one I did find on amazon for the ryzen 5 3600 showed the same price as the 2700x Ryzen 7, but has 2 less cores, the power draw is down to 65w, but both use the am4 package according to their page. So I'd personally opt for the 2700x over the 3600 if I was choosing an AMD in your case. I do not see the 3600 listed on the benchmark results in the link previously provided.
https://www.amazon.com/AMD-Ryzen-3600X-12-Thread-Processor/dp/B07SQBFN2D/ref=sr_1_2?keywords=AMD+Ryzen™+5+3600&qid=1562834494&s=gateway&sr=8-2
Best of luck, and happy hunting!