20mm options to adapt to Z

Hi all,

I am currently looking at 18-22mm lens options that I can adapt on a Z FF camera. I currently do not have any adapters but I am open to buying FTZ, ETZ or whatever required adapters. I'll be using this for mainly landscape and maybe some astrophotography so I think autofocus is not necessary. I used to work with manual focus lenses at the 28, 35, 50mm so MF is fine with me. I imagine it will be slightly different for fly by wire lenses that I have to manually focus though.

I plan on purchasing a slow 135mm lens for the compression which got me thinking adapting the sigma 20-200 E lens. Ideally I would want to keep the cost low (sub $700) as this is not my main area of photography. I'll be travelling for a couple weeks which I think not having to swap out lenses when using the 20-200mm would be a plus.

Thanks