Is there a way to extract a list of my currently enrolled/joined telegram channels at once ?
Telegram now supports data export as part of the GDPR changes, you can read my more detailed answer on another question on the site.
Specifically about your question, a demonstration from Telegram Desktop, for exporting you channels (and so you'll get to list them all, and can ignore the messages):
protected by Community♦ Aug 23 at 15:14
Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?