Vitor, you and your team are creating a very good app, the question of how to monetize it is not trivial, you are aware that competition is around the corner therefore timing for the right strategy is key

Things that your could consider:

1. Create a premium version with original badges and additional premium features like editable messages , TOR connectivity, editable filters to block trolls and reduce spam and a fancy original gift keyboard, you could charge a one time amount for life, Threema is doing that successfully. The business case will provide you with enough information to price it correctly. Threema has only one version and is paid, I don't believe that would work with Amethysts, but that is just my opinion..

Risk management; if your features on the premium version are low quality and low cost to replicate a competitor could beat you in quality and time to market. Additionally, having two versions will anger some users, weight that in.

2. Use the Signal model, donors... and consider charging for high quality badges series , that should be a trivial business case

Risk management, since you will have competitors this business case may not show great promise but with the right donors you will be running fine for years, the badges should be high quality and impregnated with your logo

3. The verification business model ,with a two layer model price. Purple free, Blue Premiun with the added features, one charge for life or year membership similar to Twitter

Hopefully you will find more ways to monetize. Your app is excellent, I for one would buy a premium version if the features offer TOR connectivity and editable filters to nuke trolls and reduce spam with list management. Paid relays IMO are non sense, if I wanted a company to filter what I read I use Twitter or any other corporate social network