My rule of thumb: never trust a service whose front page has a "Pricing" tab.

There are grease monkey scripts which should still function on the old.reddit site, even though they haven't been updated for a long time.

I don't know of FOSS "one-stop-shops" but these services should have APIs you can use and write scripts to mass-delete. It wouldn't be particularly hard or time-consuming, and you can also publish your scripts so other people can use them instead of writing your own.

Interesting tool ! Indeed, thats quiet shady to give ALL your accounts informations to a closed source app...

And alternativeto has no real alternative, rn, but let's hope something exists doing the same

It can be done fairly easily. It's literally just using the API of these services. I might try to do this while I am learning how to use Tauri in Rust.

I got a little rust program to replace all my discord messages with quotes from the uncyclopedia.