I honestly love phone calls.
- 30s on the phone covers 30m of text convos
- I can project tone, energy, excitement in ways I can't do with emojis

Group calls can die, though. What a waste of time!

The "private beta to generate more interest" thing is very product-dependent:
1) Do users have the ability to generate content? Are you trying to establish a certain expectation of quality?
2) Are you still in discovery phase/still trying to find the customer or use case?
3) Would your servers crash if 10,000 people suddenly got on it?
4) Do you need to test bugs in a production environment?

If you don't really need to run a private beta, don't bother, because there's no better way to get more people using it than making it publicly available to everyone. What may work better for your app is an invite system, every new user gets 10 invites to share with friends. Give em a bonus for sharing, feature unlocks or just a nice animation.

99% of the work getting people on comes after launch: promote the app via social media, create videos, buy ads, tell people about it in person, get press, write your own press, email out a newsletter, etc.

If you're not 100% on the idea yourself but the positive 50% is willing to put money down, sure.

Though if you're 100% on the idea yourself, who cares?

Not surprisingly, the official AWS masterclasses are actually super useful and comprehensive!

S3 (File hosting): www.youtube.com/watch?v=VC0k-…
EC2 (Server): www.youtube.com/watch?v=jLVPq…

If you're looking for a specific language, I've written/used some C# and Lua AWS libs and could probably dig up some videos from then.