Good question, with not so simple answer. An i7-4790K + a good GPU will do you some good; however, the cost of a new Ryzen 5 2600 is quite tempting compared to a used i7-4790K. If you don't have a Z87/97 motherboard for overclocking, I say go with a new Ryzen system.
You could start with a new GPU and possibly PSU if you don't have a very good PSU.
You are playing "newish" AAA titles, if this is the trend for you, then you will need soon enough to buy a new system, if you want to be able to play on high settings the upcoming gaming titles of 2020/2021.
On the other hand if you are OK playing on 1920*1080 at low to medium setting then you can keep up with your current PC setup for one or maybe two years.