When you delete your Telegram account, you'll lose all your chats, groups, and channels. So, make sure you're ready to say goodbye to all your conversations and connections. You won't be able to recover any of your data after deletion, so think carefully before taking the plunge.
If you're sure you want to delete your account, you can do so without worrying about any lingering data. Telegram takes care of everything, and your account will be completely wiped from their servers. It's a clean slate, and you can start fresh if you ever decide to come back.
How to delete your Telegram account the right way