Because you're currently on R5 1600, I can highly recommend R7 3700X for what you plan to do:
- Difference in performance will be VERY noticeable
- R7 3700X price/performance ratio is "just right"
Of course, the more you pay (R9 3900X), the better you get. But at certain point you need to set a limit and ask yourself, how much you would benefit in everyday use, for paying "a bit" extra.
As
Newtonius mentioned (above), new 5000 series CPUs are just around the corner. More powerful and more expensive... which would (in your case) probably require new motherboard as well -far from just "a bit extra".