-snip- but the Telegram's built in wallet is obviously not something you should use. AFAIK, you get no seedphrase, it's a custodial wallet. Not different than using an exchange.
There are two versions of wallet addresses in the Telegram wallet, Built in and Ton Space, for the TON Space one is non-custodial and can export seed phrases.
Yes, it will give you seed phrase which contain 24 words. But have you tested it before to know if it is BIP39 seed phrase or not? If you test it, you will see that it is not BIP39 seed phrase.
If you want a Ton wallet, Telegram wallet is the worst that I have seen because many people will think they have BIP39 seed phrase bitnitnis not.