Mike Williams they have announced Language Aware spell checking, might help with that part but not the date formatting.
"Now, Microsoft Teams users can more easily communicate using multiple languages. Users who write different messages in different languages will now see spellchecking relevant to the language they're actively using when typing a message in the Microsoft Teams desktop app.
This is a key improvement to the existing Teams Desktop Spellchecking feature, to make it "language-aware" and improve the overall Messaging compose experience for bilingual & multilingual users around the world.
This message is associated with Microsoft 365 Roadmap ID https://www.microsoft.com/microsoft-365/roadmap?filters=&featureid=65446 "