I do like to run tcpdump regularly. For a while I ran my home laptop thru an allow-listed proxy, and I was quite surprised at the results, and how little I had to allow to get what I needed done. A lot of software is phoning home. I would have thought that open source folks didn't do that, but standards or expectations have shifted. A browser that took over your DNS would have been anathema in the 90s, but now we trust the local networks even less.