As a potential buyer of the G2's, I'm super interested in the Hub, but as you can't browse the hub (AFAIK) if you don't have an account with Even, I have no idea what to expect. What apps from there have you found real usage from?
Let me start by saying that this gives you an average measurement, not something that should be clinically or medically trusted. I still recommend visiting an optician if you can.
With that said - I created a very lightweight app that uses Google's MediaPipe Iris tracking functionality, that basically gets you the distance between the center of your pupils very easily.
The app does three concurrent scans and then creates an average of the results. I tried it out with my optician results and I got surprisingly close to what my optician said (Opti: 61MM, app ranged between 59-62).
The reason I made this app is because there was no solid option for Android, and all of them that looked promising had huge costs. This app is free - no ads, no tracking, no IAP. You have the option to buy me a coffee after the scan if you want, but that's totally up to you.
I hope this helps users to get an average of their PD before deciding on which glasses to buy. Let me know if you like it! :)