How do I delete a YouTube channel without nuking my whole Google account?

Yes, deleting a channel is separate from your Google account, Gmail and the rest stay untouched. Go to YouTube > your profile > Settings > Advanced settings > 'Delete channel' (you'll re-enter your password). You get two options: hide the channel (reversible, just makes it private) or permanently delete. Permanent delete removes your videos, comments, likes, playlists and subscriptions and can't be undone, and it can take a few days to fully clear. If you only want a break, choose 'hide' instead. Download any videos you want to keep first via YouTube Studio.

Choose 'hide channel' if there's any chance you'll come back, it's fully reversible and just makes everything private. 'Delete' is the permanent one that wipes your comments and playlists too.

Grab your videos before you delete. YouTube Studio > Content lets you download the originals. Once the channel's gone, they're gone with it.