That is great to hear!
Honestly yes, it did quite feel like the ending text was done rather quickly and was a bit undercooked, but I still feel like it was able to give the impression of a sketched out diary very well. A diary isn't meant to be a literary masterpiece and should feel like jutted-out thoughts without any necessary correlation to one anoter in my opinion. If you plan to revisit that text, I would advise to keep that feel intact (but then again, it comes to personal preference and vision)
Also, no, I wouldn't like the ending spoiled. I'd love to come back to this game once it has been polished up a bit and re-experience it fully. As you said, it won't take much to go back to the ending once you properly understand the mechanics.
For a three-day-long game jam, it turned out great, you should be proud of it!