I did buy K-3III when it did come out. Not regretting it one bit. Eye/face/human and animal recognition is very good and way above anything in Pentax land, but it is not that far off from mirrorless.
Best part being that it is not a mirrorless camera. I use screen to look if my settings are good. I fo rarely rely on the screen, because itnails the shots and I can clearly see what is going on.
I did upgrade my blackmagic pocket 4K to Panasonic S5(+kit lens) which was 2000€, new in discount. I use it mainly for video. And there it is much better than K-3III. But it is slow and cumbersome(yes, it is not rated for it’s speed and usability to be the best experience for photos, which it is also not). That aid for MF is neat, but I really do need all the help I can get especially when it is not bright daylight.
Why I did bring that up. Mirrorless. Because withthis big screen K-3III has, I can see clearly, it does focus well even in dark! And it is very responsive. A joy to use, unlike Panasonic, which will give very nice video, but you really have to work for it and rotating screen is not enough, You’ll need external monitor too…(same goes for K-3III with video).
It is remarkable camera snd to me it was worth 2000€ and it will peopably be around 1800€ in few months?(christmas and all coming up) and that is even better value.
That said, if that extra performance with AF and FPS and also quite good 4K mean much, then by all means do not put your money there