FS670ES

Size benefit of crop sensor cameras vs full frame has truly gone out the window lately hasn't it?
 

That is true, but since I don't have high end video needs then it can be Panasonic S5 for me (at least good IBIS and AF not much worse in video and in stills it's actually better), A7 IV (great AF and ok IBIS) or maybe wait a little and see what Nikon Z6 III will look like (my guess is that it will be great). OM-1 is also fantastic (great size, lenses, AF and best IBIS but this sensor for stills gives me a pause though)
I am long enough with Fuji and I know that their AF and IBIS drive me crazy. Apart from that they are pretty much great. Colors, DR, ergonomics, fun factor, size with smaller primes, 4k120, rolling shutter, 1/32000 for stills and so on.

That is true, but since I don't have high end video needs then it can be Panasonic S5 for me (at least good IBIS and AF not much worse in video and in stills it's actually better), A7 IV (great AF and ok IBIS) or maybe wait a little and see what Nikon Z6 III will look like (my guess is that it will be great). OM-1 is also fantastic (great size, lenses, AF and best IBIS but this sensor for stills gives me a pause though)
I am long enough with Fuji and I know that their AF and IBIS drive me crazy. Apart from that they are pretty much great. Colors, DR, ergonomics, fun factor, size with smaller primes, 4k120, rolling shutter, 1/32000 for stills and so on.

Thank you very much. I really hoped it would be better now. I looked at the video below and though that it's quite ok but video only shows couple of scenarios. 

Coming from Fuji myself (XT3), not as good.
For stills, no problemo…in fact there are several bonuses with stills for a camera having contrast detect.
But for video, with static subjects or side to side movement, pretty OK and yes, native Panny lenses have an edge over Sigma.
Reliable tracking forward or away from you. Forget it. Pretty crap.
It CAN do it, but you don’t get to decide when those times are.
Toss a coin up in the air and the probability of heads or tails is 50:50.
That’s S5/S1 tracking as things stand for you.
 

Personally, I don't find CONTINUOUS autofocus to be usable when shooting video.
However, I usually shoot at 30fps in V-LOG, and that is where continuous autofocus struggles the most.
If you shoot in 60fps (which is only aps-c crop on the S1 / S5 series of cameras, not full frame), AND you shoot in a more contrasty picture profile (standard, natural, 709Like), then the continuous autofocus is better.
Please note that I only have one L-Mount lens: the 24-105 f/4
It is a good lens but probably the Panasonic prime lenses would focus better.
Also, Sigma lenses are notoriously WORSE for autofocus on Panasonic L-Mount bodies.