Mercurygram: a Telegram FOSS fork with Material You themes and additional features
GitHub - Mercurygram/Mercurygram: Unofficial, FOSS-friendly fork of the original Telegram client for Android
https://github.com/Mercurygram/Mercurygram
Unofficial, FOSS-friendly fork of the original Telegram client for Android - Mercurygram/Mercurygram
Yes this is a Telegram client and yes it will break the Lemmy's downvote world record but I still find this one very nice and "actively" maintained. There are not many good Telegram FOSS forks without Google integrations and similar stuff out there.