Is it okay for me to consider the future events of “The Last Problem” as merely a possibility rather than official?

In this case, despite them being part of the episode, is it alright for me to classify them as non-canon instead of canon?

I’m mainly asking because a lot of leg room seems to have been left for people to decide whether to consider them canon or not, and in my opinion...there are a lot of questionable elements and flaws in them that have made me think they’re far from canonically accurate.

I think it's fine. The definitive ending doesn't leave a lot of room for potential future storylines with the Main Six. If it had ended with Twilight being crowned, that would've been fine. From then, we could imagine what happens next.

I don't see why not It's what I do for all of season 9 and most of season 8, I mean it's not like there are people holding a gun to our heads forcing us to like the last season