For testing sure, but this needs to go to just over 1000 people.
The only example I can find online on deploying via URL is this:
https://support.securly.com/hc/en-us/articles/360036540753-H...
Can't see many official docs on it at all.
Now I've gone the Developer route I can see you can create internal apps without having to get them approved so think that's my best option now.