How can I see the changelogs of the reason of appeals?

If I can't, then isn't there any plan to add such a feature?

Those appeals didn't have a reason.

The reason can be edited before the appeal goes through. It sounds like they’re asking for an edit history for those reasons like we have with post edits.

Is there any point to having versioned appeal reasons? Except maybe a certain post that was repeatedly flagged that said something along the lines of continuing to flag it until "Reddit-tier approvers" ran out. I'm not talking about the fish for what it's worth but I won't link the post either since it'll probably be flagged again purely for that reason (of me linking it and bringing attention to the post), and only then that's if mods actually wanted to action against a bad appeal reason like that.

I don't think it would even be useful for that. How many people go back and revise their own appeal reasons? If you're talking about appeals from different users on the same post (since you mentioned a post getting flagged multiple times), we can already see the final version of every appeal in the post's Moderation history.

While ideally everything is versioned, I imagine appeal reason is lower priority than a bunch of other things (bur, comment, forum post)