Personally if I worried so much about quality (and I do) I will pick f1.4, f1.8 primes over the slower f2.8 zoom. Yes 70-200mm f2.8 is nice range but it still doesn't give you look like 105mm f1.4 or the 135mm f1.8 or the 200mm f2 (only for Canon/Nikon, not in the Sony lineup).
High ISOs most of the time bigger sensor will perform better, unless bigger sensor is using old tech and smaller is from the latest gen as technology improved over time. I am going back to the color, here is shots I have posted before. This with 16MP Fuji XT1/56mm f1.2 vs A7rII/Batis 85mm f1.8. Colors are very similar so is the DoF.


The use of UWA or wide angle is just the tool for story telling and documentation. This is where there is such great uses for zooms for different perspectives. I've found using a UWA/Mid telezoom zoom provides "more" for my style in documentation. The long lenses are for portraits, photojournalistic candids during events, landscape etc.
For outdoor family sessions I prefer using my Gmaster 70-200 and lug my heavy 105 f/1.4 for long lenses. Killer combo on my arms and back but 100% certain it delivers results.
I do watch David Oastler reviews from time to time. He's a noted the Sony A9 and A9ii have different colours. Better colours from the new A9mk2. This tells me that I'm not losing my marbles when I see different colours from lenses to other bodies/brands. Even the local Sony rep mentions how the colour science from the A73 is noticeably better than an A9mk1. However we all know colours can be manipulated in post.
I need to do more experimenting but even my Tamron 28-75mm has much different colours than my new Sigma 24-70 f/2.8 ART I just purchased. Same A73 body with 2 lenses , my the quick tests indicate the Sigma to have a much better render and definitely much improved bokeh over the Tammy.








