Mastodon has an unoffcial Android / iOS app called @tooot which catered mainly for Chinese community (plus Vietnamese & Korean)—that, tooot's UI is simple, intuitive but elegant.
✔ Multiple accounts
✔ Adjustable font sizes
✔ Dark mode supported
Following the developer's blog, his aim is contributing to the Mastodon community and help Douban refugees easy to share on new decentralized social media platform Mastodon.
More info at: https://tooot.app