The main bash script that will:

• using basically two tools telegram_messages_dump and telegram-media-downloader
• Take the chat group to check from a file
• Check if that group has been handled already or if it's new
• Either continue wih the last seen messages or start from scratch
• A lot of error handling so the script can run via crontab */4(h)
• A lot of checking of existing process to avoid deadlocks when running in parallel

The complete source is available at my (private) GitHUB repository