TL;DR: even if your delete script confirms a full wipe and your Reddit profile page shows zero comment, there may still be comments left over (that you can find through a search engine and delete manually on Reddit).
Weeks ago, I used redact.dev well before the API shutdown to delete all my Reddit comments (thousands of them over 10+ years). Redact.dev confirmed a full wipe, and my Profile > Comments page on Reddit confirmed I had no comment left.
Yet, as of today, Google still returns dozens of results for “$myredditusername site:reddit.com”. It’s not just Google’s crawler lagging; when I follow those links, those comments are still visible on the Reddit website, under my username, where I have the ability to manually delete them.
Thankfully, I hadn’t yet nuked my account because I knew of other users whose deleted comments got reinstated (although that was thought to be caused by the deletion script exceeding the API rate limit; supposedly a different case, as they should show in the Profile page).
So even if your Reddit profile says you have no more comments, use a search engine and you may find plenty of leftovers.
spez: edited for clarity.
Correct, github shreddit for example can do this, it has builtin support for checking the GDPR archive and finding comments and posts to delete/overwrite that way.