it is better to migrate the helpful comments to lemmy, after thischange the comments to nonsense than to delete it:
https://www.reddit.com/r/RedditAlternatives/comments/146lloj/protip_if_you_replace_the_content_of_your/

“: if you replace the content of your posts/comments with nonsense, you’ll make Reddit Inc. (including its CEO) lose money.”

"There’s a good chance that those API price changes were motivated by large businesses using Reddit to train their large language models (LLMs) with. Stuff like GPT-3, Google’s BERT, Facebook’s Galactica, stuff like this. In other words, your content will be used to train bots. (It is, already.)

Those models can be “poisoned” with random, machine generated nonsense. Poisoned data is worse than useless: it makes the model worse. So for each person replacing their Reddit content with nonsense, those businesses will be willing to pay Reddit Inc. less and less for API access."

"Here is a mini-tutorial on how to do this. It’s for desktop users but you’ll likely be able to do the same from a phone browser.

• Open Zompist’s gen. Take off the line saying “ki|či”, and click “Generate”. You’ll get some random babble like “Bepe topioi kabi brete i kropra”, copy it somewhere.
• Open your Reddit profile and drag the button of Power Delete Suite to it.
• [Optional] Check the box saying “prepare local backup of items”, if you want to save your content elsewhere.
• Uncheck “remove comments”. You want to replace them with babble, not remove them.
• [Optional] uncheck “remove posts”. It depends if you post mostly self posts or if you post links/pics. Use your reasoning.
• Check “Edit comments / self posts”. It should open an input box for text; place the babble from Zompist’s gen there. Then click “process”.
• Just wait!
• [Optional] Click to download the backup of the items.

If you don’t like Zompist’s gen and/or Power Delete Suite, you can use any generator and/or Reddit mass edition tool of your choice."

and yes, i am somewhat still on reddit but i think i do more against them when my app does not work anymore (to spread lemmy or information) i will follow this process