You asked
Is the sigma 24mm f 3 5 dg contemporary good for street photography?
Yes, I think it's a good street lens. It's a pocketable wide prime, and street shooting rewards gear you can carry all day and barely notice. On APS-C it frames like 36mm, a classic street focal length, and f/3.5 there gives about the depth of field of f/5.2, which makes quick zone focusing easy.
I'd pair it with a small APS-C body. My picks from the list of cameras it fits are the Sony a6100, the Sony a6400, and the Sony ZV-E10 II. A full-frame body works too, but as I say in the sensor guide, a lighter APS-C setup is usually the one you'll actually carry.
Whatever you shoot, be open about what you're doing, and delete a frame if someone asks. More on that in the street guide.
Written by Claude from this site's pages.