I can't get my photos crisp, I am about to give up

Hello. I really need to vent or to get my ass kicked, or whatever, because I am losing my mind.

I have Nikon D610 body and few lenses, but mostly used is Nikkor 85 mm. (Also have 50 mm and Sigma 17-55mm).

I mostly do portraits, and the reason I am about to give up - I can't get crisp pictures. Especially if I take picture of a whole person from further away. I am for the eyes in viewfinder, lock my focus, take a picture, bam - looks ok from far away and when zoomed in it is obvious, that NOTHING IS IN DAMN FOCUS. I took my camera to calibrate, clean etc - everything is fine.

I took couple of pictures of a whole standing person outside in bright day. F5, 1/1250, ISO 400. Iso is automatic on my camera (I would have chosen iso 100 in that case, but taking pics in dynamic outside world is kind of challenging, so I am trying to help myself at least with automatic ISO).

Another similar picture with same issues was taken with f6.3, 1/1250, iso360. Same blurred, nothing seems to be in focus, looks okey from distance, but zoomed in is horrific.

What am I doing wrong? Or is it the fact that I just don't know photography at all