There’s 4 different types of channel URLs.
- Get a channel URL by visiting your YouTube channel and copying the link in the address bar. (https://www.youtube.com/channel/UC_WFBgnP5s2fvVhj8LPjLNg?view_as=subscriber)
- Get an ID-based URL by taking “?view_as=subscriber” out of the channel URL.
- Get an optional custom URL after 100 subs, 30 days on YouTube, having a photo as a channel icon, and uploaded channel art.
- Legacy username URL is a kind you can no longer get on YouTube.
P.S. ID-based URLs don’t change but a custom URL could. I found this out from here: https://support.google.com/youtube/answer/6180214?hl=en