Is there a way to convert contents of TData into .session of WTelegramClient?

[ashelemba]

No description provided.

[wiz0u]

We don't support the import/export of sessions obtained from other libraries or external sources (fake accounts bought from shady Internet vendors? extracted from official clients against the TOS?).

If you own the phone numbers, you can easily create new sessions by answering the verification code sent (via existing app or other methods) during the login process.
If you don't own the phone numbers, you're likely going to be mass-managing multiple accounts for nefarious purpose like spam, scam or other manipulation, and this goes against Telegram ToS (https://telegram.org/tos) or the API ToS (https://core.telegram.org/api/terms). We don't support this practice.