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.
Does it have tools to easily remove deleted accounts from groups? Or selecting several contacts from your contact list and deleting them? Because those are big features missing from telegram
For the group thing, I would expect at least a way to search/filter those accounts while looking at the group's participants, even if I do have to manually remove them. Having to endlessly scroll a list with no apparent order is not fun.