For all of the built-in adapters to work, you'll need ffmpeg, pandoc, and poppler-utils. See the Scoop package [1] for a specific example of this.
> does it create a bunch of caches, that clog up storage and/or memory?
YMMV, but in my opinion ripgrep-all is pretty conservative in its caching. The cache files are all isolated to a single directory (whose location respects OS convention) and their contents are limited to plaintext that required processing to extract.
