I did the exact same thing, also with a link that redirects you to a tutorial explaining how to get started with Lemmy. Took about 7 hours but the script actually succesfully edited every single comment I ever made.
I’ve done that with some of my accounts, and my friends did the same. The accounts that linked to Lemmy, Kbin or Mastodon were shadow banned. Manitcor’s solution (another reply to this comment) might be a better option that glides under autobot-radars.
Be warned: I used the same script to automate changing all my comments to nonsense, but I found a couple of days later that Reddit had changed them all back.
It's your decision, and I hate Reddit and Spez ever since they decided to do the whole API thing, but personally, if I were to close my account, I wouldn't scramble all of my comments and posts. It makes it harder for people who still search for answers to questions on reddit to find what they're looking for. You aren't preserving valuable information with this, you're destroying it.
I scrambled years worth of comments into a statement about the fuckery Reddit has committed and left those edited comments intact while deleting my accounts.
This serves a couple of purposes:
Devalue the platform by destroying information, with the explicit hope that it fucks with Google results and that people will leave if enough people salted the earth on their way out