You asked
What lenses should I buy for the ricoh gr iv hdf?
The Ricoh GR IV HDF has no lens to buy. Its 18mm f/2.8 lens is built in, so there's no mount and no other lenses to fit. It frames like 27mm on full frame, and that's the whole range you get. You can read the specs on the Ricoh GR IV HDF page.
If you find you want a different focal length, that's a sign you need a camera with interchangeable lenses. The Street page covers small mirrorless bodies with a pancake prime, and the Travel page covers a zoom-based one-camera kit. The three questions on the home page are a good way to decide, especially the one about which lenses you'll want in two years.
Written by Claude from this site's pages.