I've never owned a dedicated Blu-ray player but I've been watching them on my Xbox for years and this got me curious so I disconnected it from the Internet and grabbed a few discs to test.
American History X, Mad Max Fury Road, and John Wick 3 with Blu-ray package release dates of 2009, 2015, and 2020, respectively. All three Blu-rays play just fine with no Internet connection. Unfortunately I don't have anything newer to see if this is a more recent change.