I have never used nextcloud before, so I am not sure how to install an app. I created a nextcloud account that was pointing me to the a server with the address https://the good.cloud. With my credentials and this server address, I can log in to this nextcloud instance via the nextcloud android app. I don't see any options to install apps there though.
Is it possible to install apps in nextcloud when you are not self hosting? If so, how do I do that?
Never mind, I figured out that indeed this service just doesn't allow me to install apps. If someone knows about a free nextcloud plan that does allow you to install apps, please let me know.
I doubt that any free service exists allowing apps. If you can shell out some 5$ per month, you may want to look into Hetzner Storage Share. You get 1TB space and you can install quite a lot of apps, create multiple users and so on.
You need to be an admin on the instance, and on the web client. Once you are there, click on the profile picture/initials and click on “Apps”. The app store should open.