.com and .com.br registered. And now?

Guys, I'm developing an app and had already created the name.
It's the ideal name for the app, I don't want to change names.
But the domain .com and .com.br (Brazil) are registered. .Com is selling for a very expensive price (+$2k) and the owner of .com.br does not want to sell the domain (neither uses nor wants to sell).
What extension do I register? I was thinking about .app.
Suggestions please.

If I can't obtain the .com I usually go for the .net.

For software, I always go .io or get{appname}.com, or when both are taken, both lol - getshout.io

You should go for .io if available. It is suitable for a tech company/app and better than .com.br which will leak your type-in traffics to .com website.

You also have the option of .app for less than $20.