Alright. I just naively assumed that most bots would be classified as
"desktop", given there's practically never a good reason to crawl the
mobile domain, so I was surprised by the numbers. Either there's a lot
of "bot" activity on the mobile domain, or there's very little "user"
activity on desktop.

You can always go directly to the API. The addresses are slightly human friendly but you can always log XHR in your browser console and copy them. Here are some examples for the last month of data:

mobile web automated: https://wikimedia.org/api/rest_v1/metrics/pageviews/aggregate/it.wikisource.org/mobile-web/automated/monthly/2020050100/2020060100

desktop user: https://wikimedia.org/api/rest_v1/metrics/pageviews/aggregate/it.wikisource.org/desktop/user/monthly/2020050100/2020060100

By the UX improvements I mentioned above, we'd surface this ability in the UI