REJECT ALL button doesn’t often work as you’d expect. Websites/Apps can (and do) still approve so called “legitimate interest” option. The only way to be sure is to click “manage preferences” and dig in to check if legitimate interest is enabled. Sometimes you’ll see “object all” in there, but you will find notice that some websites require to manually disable legitimate interest for each of the hundreds of partners manually.
Not to mention being forced to create a MS account if you’re online.