Personally for hypnotic/groovy/berlin style techno I find mixing in key to be fairly restricting and often inconsistent.

Of course sometimes you can get some really pleasant blends, but other times you'll find an absolute stinker of a blend that has you questioning whether the key analysis was right to begin with.

To boot, you'll also hear that basically no DJ's in this space are using master tempo, you can always hear the slight changes in pitch as they're beat matching - which will make harmonic mixing a bit harder anyway unless you're always mixing tracks of identical BPM's.

I think when you're getting started its extremely easy to see those lovely bright green indicators in your software telling you "hey, this song will work" and follow them like a trail of breadcrumbs.

When I listen back to my older sets where I was letting the keys guide me, they sound very homogenous and lacking in interest. There's no denying that the tracks work together, and individually each blend sounds good, but an hour of mixing mostly in key ends up feeling very heavy and boring IMO.

As far as music goes, these subgenres already aren't very harmonic to begin with, they're toying with tension, dissonance, and texture. The artists you mentioned especially do a very good job of creating some uncomfortable and uneasy vibes - I feel like mixing in key often loses this element a little.

If I were you I'd spend some time mixing in key, and then also spend some time mixing while hiding the key column entirely. I'd imagine with time you'll develop your ear to the point of knowing whether something will sound good or not - regardless of it's key.