I would echo the advice of using a test framework. An alternative would be a browser extension, and using that to query the element ids while manually visiting each site.

The requirement to make it not tied to a Google account rules out what would be my preferred method of getting these via the YT API.

I think there are some open source git repos that already do what you're asking (e.g. https://github.com/egbertbouman/youtube-comment-downloader) but I haven't personally tried any of these.