Which one to upgrade...???

[zer]

Hi there!
Current system: I5 8400, 16Gb DDR4 2400, GTX 1070, z370mobo
Problem: Currently, I noticed frequent dips in the most demanding scenes, or demanding games in general (Metro Exodus, AC Odyssey etc) I am pondering on the order I should upgrade things, to get the best value for my euros. Options (according to me...)

1. Upgrade Ram speed to 3200 or even 3600, low CL (14? 16?)
2. Upgrade CPU WITHOUT CHANGING MOBO. Something like i7 9700K.
3. Upgrade GPU to RTX 2080 (Super or non super...) or 5700XT

Opinions please? Thanks in advance!!!

 

[zer]

Thanks for the answers!
1080p, 144Hz monitor
I was considering that i5 8400 will bottleneck 2080, so it should be upgraded first (with same mobo).
I also saw youtube clip that demonstrated big gains going from 2400Hz ram to 3200Hz. EVEN IN INTEL (which surprised me)

 

[zer]

So, to sum things, first something like DDR4 3200 CL14, then i7 9700k (after the price drop, should that happen...) and finally the GTX, maybe after seeing what else AMD has to offer , besides 5700XT.
Sounds right?