You are right, according to this [1] Fennec is discontinued in favor of Fenix! I only use it for very simple stuff (HN, selfhosted apps etc.), so I did not notice. Yet, looking at the F-Droid store [2], Fennec indeed is available in a recent version (109.2.0) and it is being bumped by Mozilla [3].
[1]: https://www.reddit.com/r/firefox/comments/ih9vmb/firefox_for_android_fenix_79_release_fennec_is/
[2]: https://f-droid.org/packages/org.mozilla.fennec_fdroid/
[3]: https://gitlab.com/fdroid/fdroiddata/-/commit/0861f91fd39e56a13a7664e588fcf53860e0d7ba