Google will give you a file with all your subscriptions. Muuted reads that file and adds every channel as a source. About ten minutes, most of it waiting for Google's email.
Google Takeout is Google's own export tool. You only need one small part of it.
Channels count as sources. The free plan includes 100, so a big subscription list may hit that ceiling; Muuted stops there and tells you, and nothing is lost.
No. The file is the only thing that moves. Muuted never signs in to Google, and it reads public channel feeds after that.
Probably everything was still ticked. Go back to Takeout, click Deselect all first, tick only YouTube and YouTube Music, and inside it keep only subscriptions. The export should be a few kilobytes.
Yes. Search a channel by name in Muuted or paste its address or @handle. The file is just faster when you follow dozens.
No. Channels you already follow are skipped, so re-importing after you subscribe to new ones just adds the new ones.
Different apps, different exports. Import your podcasts covers each one.
Start with 100 sources and 10 muted words free. Founding Pro is $4/mo or $36/yr — later $5/mo · $50/yr.