I have a handful (literally, like 20) points that I need to create three radii around— 200m, 1000m, 2000m— so that I can extract raster (land cover within the radii) and vector (road length within the radii) data from those. Does anyone have any idea how I might create those radii and perform that analysis? Seems like a simple enough task, but I'm figuring this all out on my own. Using QGIS 3.10!
Conceptually for each of the three distances you want to Buffer the points, and then use these buffers to Clip the land cover and road data. Specifically use the Raster Extraction tool to clip the raster landcover data, and Clip Vector by Mask Layer for the road data. In both cases your buffer will be your mask or clipping extent layer, so you'll need to run all the steps once per buffer (radii) distance.
The QGIS "A Gentle Introduction to GIS" page on buffering and the QGIS Processing Guide's page on Clipping and merging raster layers give some examples that could be helpful to understand the underlying concepts.