Being paranoid, I ran a VM just for Facebook. The browser never went to any other sites, so as far as I know there is no way it could track me or get any actual information about me, other than maybe a very rough location based on my IP. I also setup a burner email just for this and used a fake name/picture.
On a fresh account with no info, my feed was much like that of the linked article. A bunch of thirst traps and various "news" and memes. Occasionally it would tell me to follow stuff so it could actually populate the feed, but when it wasn't doing that, it was giving me this kind of garbage. This was before the advent of generative AI, so I assume these were mostly real photos, but who knows who was actually behind those accounts.
Twitter was fairly similar, but would show a lot of high school kids fighting or general street fights... along side the thirst traps.