Building a full-frame rig: Nikon z6 or Sony A7III?

[TomPhoto23]

First post on the Forum, nice to meet everyone:).

I would like to step into the FF videography world, currently looking at the Sony a7 III and the Nikon z6. Watched a few comparisons on youtube but the latter is not the best way to get an impression thanks to its heavy compression.

My preferences:

- Good focus tracking (hence no Panasonic, sorry...)

- Top image quality at high iso: supersampling of the entire sensor

- Good color profiles, log

Questions:

1. I do see some artifacts (Moiré) on Nikon's sample (Dpreview link), can these arise from oversharpening?

2. N-log is unfortunately not available for internal recording like Sony's slog. Does the 3rd party "z-log" provide an equally good way to extend the dynamic range? (i.e. record information from previously omitted bits)

3. Is the bandwidth difference (144 vs 100Mbps) significant in case of Nikon vs Sony? (I know all codecs are cooked differently...)