Mastodon has just released their official Android app. The play store still takes me to Tusky which is a 3rd party mastodon app. Using the link directly works for me to get it installed. https://blog.joinmastodon.org/2022/04/official-apps-now-available-for-ios-and-android/
They also have an ios app. This instance doesn't show on the default list, but you can enter the URL social.troxelhome.page to login. I noticed that for me there is a bug that you have to press enter in the keyboard because the button on the app doesn't activate when you enter the URL.