The gotcha is if your phone defaults to open all urls with the browser… then you’ll get the 404 error.
If so, try go to your Android settings > Apps & Notifications > Default apps
At the bottom of that list you should find an entry for “Opening links”, click into that.
Scroll down to Meshtastic, click into it (hopefully you do have this app listed).
You should see “Supported links” listed, showing that urls to www.meshtastic.org.
Click on “Open supported links” and choose to “Open in this app” or “Ask every time”.
Hopefully now when you click on the channel URL, it’ll pass it to the Meshtastic app to handle.
Good luck.