This should be a different post, but it depends on what you're planning to do with them. Enums are flexible and could totally make do there regardless of semantic cyclical-ness. Remember with enums you're able to just ignore the values altogether; that's one of the major reasons to use them. If I have a limited list of flags that I use directly in code, they don't have to change at runtime, and don't need additional data associated to them (like 'number of days' or something similar), I'll use an enum.
If you wanted to actually cycle though them in your code, it might be clearer to use both a manager class with a enum. Inside the class, you could use a something like a CurrentSeason property and have a NextSeason, PreviousSeason method to cycle through them. Using modular arithmetic would allow you to change the number of items to cover future features like seasonal transitions or something without having to modify any of your code.
I am obviously not a lawyer but I don't see how Reddit is in the wrong here. On GDPR.EU that "The EU’s GDPR only applies to personal data, which is any piece of information that relates to an identifiable person. It’s crucial for any business with EU consumers to understand this concept for GDPR compliance." I don't see how your comment history would be considered "personal data".
It even says in Reddit's TOS that "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".
You've agreed that your posts are no longer your "personal data" at that point...