If so, will both matter and energy cease to exist?
Matter will, the hypothesis goes, decay into photons, which takes a long, long time. Then that energy, in the form of photons, will speed through the universe with nothing left to hit and will eventually redshift to flatline. And, no, that energy does not disappear. It is converted into the expansion energy of the universe, which now has nothing in it.
Humans by nature try and predict things...like the weather, a political race, or the future effects of harmful chemicals. We are trying to determine our future. That in and of itself is not harmful.
The harm is in fooling yourself, and possibly others, into thinking that everything CAN be predicted. You, for example, are arrogant enough to think that the voice of Jesus in your head is telling you "the answers" - and that those answers are right despite all evidence to the contrary. The harm is in gullible people like you being taken in by evil people like Trump who are intent on bringing on a Fourth Reich.
In addition, I do not believe that the future of the universe is random. It has a definite destiny.
Heat death may be the ultimate destiny but every step along the way is random.
"Oh no, They've gone and named my home St. Petersburg. What's going on? Where are all the friends I had? It's all wrong, I'm feeling lost like I just don't belong. Give me back, give me back my Leningrad." -- Leningrad Cowboys