Focus Hunting Issue with a6400 and Sigma lenses

[Caylen W]

Greetings everyone, my name is Caylen and I'm completely new to this forum. I'm not a professional photographer/videographer, I'm a hobbyist that's using photo and video for my business for content generation. 

I'm using a Sony a6400 coupled with the Sigma 16mm f1.4, the Sigma 30mm f1.4, and the Sigma 24-70 f2.8

I also have the kit 16-50mm but I'd rather not use that if I don't have to. 

My problem; severe focus hunting while shooting video in Auto Focus. I've scoured the internet and I've come up blank. I'm not interested in using manual focus if I don't have to, but if there's no recourse other than that, I'd rather hear it from subject matter experts.

I've tried all the AF selections, with face/eye detection both on and off. I've got my AF sensitivity and drive speed set to standard and normal. 

Any help with this would be greatly appreciated!