I want to delete all the comments I have saved up through the years but I was wondering if I click on delete all comments will it delete only the comments written on my profile? Or does it also delete the comments I have said?

Just deleted like six years of comments to test this out. It does not delete comments that you've made on others' profiles. If you want to do that, you have to individually go to their comments and delete yours one-by-one.

Thank you for letting me know. I had the feeling it would do that so I started deleting my comments one by one haha.