OMG

that is Mega Thread!
Considering to join Sony family and buy Sony A7III- mainly for landscape. Looking for some advice, tips. Would like to know what lenses you use. I guess I am in the right place?
The lenses depends on what sort of landscapes you shoot.
Mid range zoom I would say the 24-105 f4 plenty sharp enough espically at traditional landscape apertures and a very handy focal length - rally impressed with mine. You can push the boat out and get the 24-70 GM or there is the Tamron 28-75ish? that gets good reviews.
WIde angle = if you want a zoom the obivous choice would be the 16-35 either the f4 or the f2.8 GM depending on your budget.
If you happy with MF on the wide angle end it can include the Zeiss Loxia 21mm, Laowa 15mm f2 and the Voigtlander 15mm f4.5 all excellent lenses.
Telephoto end you have the obvious 70-200 either the f4 or f2.8 but I good lightweight cheap option would be a 200mm f4 prime from Canon, Olympus etc can be had well under £100 along with a £20 adaptor you can get lovely results at f8-f11.
Personally I went with the Sony 24-105 f4, Zeiss Loxia 21mm, a Laowa 15mm for Astro (a 16-35 would probably make more sense but I really fancied the Loxia 21mm) and I have a Olympus 200mm f4. I do have the Sony 100-400 but if Im walking any distance I normally take the Olympus it does suffer from a lack of contrast and CA but both can overcome in post.