I'm an hobbyist, I'm 25, I use a sony a6000 and I suppose I will remain on sony for a long long time because of prices and weight.
I mostly like landscape, architecture and portraits but I also take a lot of still life.
I only have the kit 16-50 3.5/5.6 and a nice sigma 30mm 2.8 that I really like.
I'm looking for a nice whide angle. My first concern is to have the less distortion possible, because I really want straight lines, then a good aperture to be able to shoot on hand decently even with low light.
I like autofocus, but I'm well used to full manual, so, nevermind.

I'm considering:
600€ - Laowa 9mm f/2.8 Zero-D ( my favourite by now, but all the money I can spend for photography now)
500€ - Rokinon/Samyang 10mm F2.8 ( Probably not really worthy considering the Laowa competitor )
300€ - Rokinon/Samyang 12mm F2.0 ( affordable and fast, but with a lot of distortion. )
900€ - Carl Zeiss Touit 12mm 2.8 ( too expensive, but it's interesting to discuss it )

I don't have much experience, but using my 16mm 3.5 I really feel that I'd like a faster and wider lense. Any suggestion and consideration?