This looks like the effect used on Rey in The Last Jedi, also on Sandra Bullock in Bird Box.
I own the a7III and have compared it side by side to the GH5: the a7III is much better in low light, even with a speed booster on the GH5. Also, I haven't seen any advantage of Panasonic's 10 bit 422 compared to Sony's 4k 8 Bit, they look nearly identical in DaVinci Resolve (in my opinion). I have zero complaints about owning the a7III (I started filming with Canons seven years ago); I would recommend this camera to anyone looking for a small form factor video camera.
I think that some of the a7sIII predictions here are very wishful thinking. I think it's a very slim chance of it doing 10 bit, even to an external recorder. Since the a7sIII will be more "video focused," I'm betting the only advantages it'll have over this a7III is: 4k 60fps, maybe a HFR option like 240fps in 1080p, and of course it will be even cleaner in low light. I can't imagine it offering much more than that given their history.
I shoot with the 70-200 during the ceremony on my left and right side cameras; I can get close up shots without being a distraction. Since you're filming in 4k with the GH5, you could crop in to get even closer. These videographers have some really nice/ expensive gear, I see no reason why they couldn't have filmed with longer lenses to get their close ups.
As a wedding videographer, I totally get that the couple is paying you to get certain shots and be "creative", but I would personally never get two feet behind the couple during their vows to get a shot. At that point, you're taking attention away from where it should be. The couple, their bridal party, and the parents sitting in the front row are fully aware of what you're doing and now they don't have 100% of their attention where it should be: on the couple. Their memories of that moment will now include you, which it shouldn't. The shot looks great in the final product, but it comes at too high a cost in my opinion.
I don't like being critical of other wedding videographers work, but I think this is a bad practice to propagate.
I think it's interesting that Wally Pfister directed some of these episodes using the Red camera, given that he's been a huge supporter of using film for his projects.