The 5600x for 389 is a MUCH better deal than the 10850k for, anything that not less than 389.
https://www.cpubenchmark.net/compare/AMD-Ryzen-5-5600X-vs-Intel-i9-10850K/3859vs3824
Because, the single core performance is better on the 5600x, and nothing is currently going to use all of the threads on the 10850k anyhow, so the fact that it has better multithreaded performance when all threads are in use means very little unless you plan to run a title that has extremely good multithreaded optimization (Which isn't all that many of them, even in 2021) and can utilize more than 8 threads total (Which again, is few of them) AND will be also heavily multitasking with processes for simultaneously recording, streaming, browsing, and whatever else you can think of that you might be doing WHILE gaming.
If you don't plan to do much of anything extra WHILE gaming, then those extra cores are not very (Or at all) beneficial once you get past about 8 total threads for most situations.
Plus, you'll need MUCH more extensive cooling considerations for the 10850k than you would for the 5600x, meaning more extensive case cooling and a higher end CPU cooler as well. All of which are additional expenses if you don't have something that's already capable enough for it.