You don't need to use the official Mastodon apps, they're not the best way to use Mastodon. The official apps only arrived last year, and they were intended as "Fisher Price My First Mastodon" things with a restricted set of features.
Third party apps have been around longer than official ones, and include way more features. You can sign in with the same account on all apps.
On Android try Tusky, Fedilab, Megalodon, Tooot
On iPhone/iPad, try Toot!, Ice Cubes, Ivory, Mona
@feditips Any free clients for iOS (except Ice Cubes)?
Mona has a free mode and a free trial of the full mode.
It is okay to pay for Mastodon apps though, because this is a sustainable way to fund their development. They generally don't collect data or show ads, so they depend on payments or donations to keep doing.