You don't really buy a lens solely based on the "specs", you have to know what you can do with it.
For the discussion of focal length, 35mm and 55mm each has its own way of shooting. With your A7rii, you can even "cheat" quite a bit with cropping so that means with 35mm you can actually crop down to 50mm-ish while maintaining good enough resolution, and for 55mm and so on.
As for f stop, well you can easily bump up your ISO for the 1+ stop of light, no biggie I think.
If you shoot RAW, you might wanna stay away from FE28 as the distortion is quite bad and hard to correct. I have the lens to pair with my A7ii, mainly for lazy time and for people to help take photo of me... But not to say it's a bad lens, it's superb for what I've paid for it.
If you're not in urgent to get the lens or leaning more towards a 50mm, wait for the upcoming FE lenses. Even Samyang is coming up with a 50mm f1.4 and the price will most probably be very reasonable.