No. Just claiming your own rules over existing rules is the same crap that those sovereign citizens are trying to pull. As much as I hate reddit (being an now ex 13year redditor) this is not something you fix plby putting your own license in your post, it makes you look … Well, like those sovereign citizen types. Dumb.

Of course, you can check the licensing terms of all comments and posts in the EULA:

https://www.redditinc.com/policies/user-agreement

It would not. Because when you signed up to Reddit, you accepted their user agreement, which you can read here in full: https://www.redditinc.com/policies/user-agreement-september-25-2023

As you can see in Section 5: Your Content, you have already consented to following:

You retain any ownership rights you have in Your Content, but you grant Reddit the following license to use that Content:

When Your Content is created with or submitted to the Services, you grant us a worldwide, royalty-free, perpetual, irrevocable, non-exclusive, transferable, and sublicensable license to use, copy, modify, adapt, prepare derivative works of, distribute, store, perform, and display Your Content and any name, username, voice, or likeness provided in connection with Your Content in all media formats and channels now known or later developed anywhere in the world. This license includes the right for us to make Your Content available for syndication, broadcast, distribution, or publication by other companies, organizations, or individuals who partner with Reddit.