That really requires a crystal ball...
Otherwise, you're trying to prepare against/mitigate the impact from upcoming software updates and hardware launches - neither of which you, I, or anyone else, has any idea about regarding drivers, new features, performance impact, etc. - that won't make yours look totally obsolete in a few years or so.
It is an effort in futility, and the only other answer anyone could give you would essentially be second-guesswork, unless they're time traveling Terminators or own a TARDIS.
That said, you'll never see 5+ years out of a gpu and still be relevant, unless you play at 720p or 480p, 2 resolutions that rely very little on gpu horsepower - oh, the irony...
The gpu is the device that tends to show it's age first.
Cpu: Things look to be heading towards utilizing high thread count processors, what with the tall hurdle that is the 5.0ghz wall.
Will it stay that way? Of course not - but for how long?
¯\
(ツ)/¯
10700k + 2070 Super or 3600x + 2080 Super
Combo 1 is a wash. Combo 2 is more attractive.
If you can't afford to go big all the way through, you won't gain that performance edge that comes with an Intel cpu; you have to throw value out the window.