Can confirm. I uninstalled the app and then reinstalled from F-Droid to see if that would allow me to access the Hamas channel. Now I can't log in lol. It says that it's trying to send a code to my Telegram account, but I don't know how to log in. Seems like problem might be that I didn't log out of Telegram before uninstalling. Others have reported the problem on Reddit and Quora, but there aren't any solutions beyond contacting Telegram support. Oh well.

Update: I reinstalled Telegram from the Google Play store and was able to log in again. After I did, I noticed a message from Telegram explaining that I could download the .APK file directly from the Telegram website to avoid restrictions. I was able install and log in that way, but I still had to get the login code from the Google Play version. Anyway, I can now access the Hamas Online channel again from the APK version.