Quick guide on how to play YouTube in a podcast app from your share sheet
1. Install "Shortcuts" if you don't have it already
2. Go to Settings → Shortcuts and enable Allow Untrusted Shortcuts
3. Install Listenbox shortcut
Now you have Listenbox in your share sheet. Tap this button and choose "Listen"
Go ahead and do this with other links on the web
If you don't have a podcast app, Overcast is cool