You can read about Fedora’s release life cycle here:
As this page states, “Release X is supported until one month (4 weeks) after the release of Release X+2.” So, Fedora 33 will be supported until one month after Fedora 35 is released. Based on this schedule, it looks like they’re currently expecting Fedora 33 to go EOL on 2021-11-16 (likely subject to change).
Thanks, @anon40932131, for pointing out the announcements. 