I already have a script that's doing this work, it scraps: Id, username, first_name, last_name, last_seen (as at the time the boy was run), type (if this user is a human is or a bot).
The only thing that is not in it currently is when the user joined which I can also implement. Within few hours if you accept my offer
Note: Telegram place a limit of 10k to groups/channels having more than 10k members. But I have a way of by passing this limit and scrape app members available on the group