I have an A7iii with a 24-105 like you; I bought with it a 16-35 f4 for churches, castles and museums that is wherever is space is limited.
As primes I have a FE 28f2 and a 90f2.8 macro. I like them both. I use the 28 mainly where there’s low Light and the macro for insects, of course and, portraits too.
Now I am thinking about buying the 55 f1.8 for full body portraits and low light shots but I’d also like to get a wider prime for landscapes and astro shots. I am considering the Zeiss Loxia 21 f2.8 and the next coming Sony 24 f1.4.
I’m aware there are lenses by other manufacturers but native ones like Sony and Zeiss are smaller and lighter.
This is only my opinion which differs form anyone else’s because of my kind of shooting.
I wish I could afford a Sony 12-24 f4, if only because sometimes in internals I find myself a bit narrow with the 16-35.