Hello. I can assist you with your question.
It's an extremely complex one.
Some of what you are describing is correct.
Except for the reference frames.
If YOU are getting close to the even horizon, because you always observe light at a constant speed, nothing changes.
However, from the perspective of someone far away, looking at you, your clock would appear to slow down, and at the even horizon stop.
But for you, time would go by normally.
But I think the second part of what you are saying actually takes what I've said into account.
That is, from the reference point of, for example, someone on earth, your clock would come to almost a complete stop according to them.
So a century for them could pass by, while you have experienced less than a second.
So if you were to return to earth after a prolonged period of time near the even horizon of a black hole, many years would have gone by on earth - perhaps thousands, hundreds of thousands, or even millions of years - potentially in what was only a few seconds to you.
Absolutely FASCINATING topic.
Oh... so you would see the "future of the universe", but that future universe would always be your "present". You would be "in" that future universe and not simply observing it from a time in the past. Therefore you can't go back and tell someone what you saw.
That's not possible.