35 ART w a Canon 6D issues

so I did my intial test run with my son and was blown away with the image quality and overall use of the camera. Spent money on a model planned a trip and afterwards doing post was amazed by how many of my shots are out of focus. The camera was giving me the beep as if it was focused on her eyes yet some were even focused as far back as 5 feet. That was with the model even standing still. Now I know the 6d has limited focus points but it seems to be the sigma where most other users have had issues. I know I can buy a dock but plain and simple i have watched the videos I don’t think I’m gonna be able to handle it. Question one how do I know if the issue is with the camera or lens or both ? Question 2 is there anyone in the NJ NYC area that has the canon dock that would possibly sync my 35 ART ? Or 3 what would your advice be to me ? I was also possibly considering the Tamron 35

This is unfortunately a fairly well known issue with the 35mm Art with both Canon and Nikon. The first generation of Art lenses (35mm, 18-35mm, 50mm), all suffered from inconsistent focusing issues in the viewfinder. Some have hypothesized that the issues were due to the weak AF motor, which Sigma has improved since then. You can try tuning the focus using the dock.

The foolproof solution I've seen is to send your camera together with the lens to be tuned by Sigma.

Mine had the same issues and after calibration, it is perfect.

Get yourself a folding lens calibration card, get the dock and get to it.

It's a little fiddly, but with patience you will get the Sigma tuned exactly how you want it.

I have not seen an OOF image from mine since I calibrated it over a year ago.