yo. im a little late but i think i know what youre going through, at least a little. 4 or 5 years ago, i would frequently get these horrifying thoughts. i believed that there was a 'heaven', i pictured that for eternity id be playing tag, chasing someone in a small circle for eternity, the scenery being an infinitely blank, white space where i could go one direction for eternity and itd seem id still be in the same spot. like the spongebob episode SB-129, this scene: https://www.youtube.com/watch?v=LoOy4_F2a44 (except like totally blank)
i also watched the show "The Good Place" which explores this philosophy. it takes the common lukewarm human idea of a 'reward' and follows it to its logical, exhausting conclusion.
recently i learned that i was trying to solve an infinite problem with finite tools. we get bored on Earth because things here are static (they decay). we naturally think 'forever' just means 'a really, really long time' and that is exhausting to imagine.
what changed for me was that realizing if the Creator of the universe is actually infinite, meaning He has no end to his creativity, beauty, or wisdom, then eternity isnt a loop. its more like an endless exploration. instead of a white void, i started seeing it as a 'New Earth' with more texture, color, and activity than we have now. u dont need an 'off switch' when every moment is better than the last. again, as humans, we cant grasp the whole idea of eternity and infinity. i kept trying to understand that part but i got myself in another loop like how i was right from the beginning. the Creator's creativity, beauty and wisdom and this 'New Earth' aint gonna be like 'wow congrats! u found grass blade number 4,091,838,929', but its literally an entirely new, ever so beautiful and creative masterpiece that will always bring meaning, value, importance and all.
for me, getting to know the character of God is what took away the dread. when i stopped seeing Him as a distant, 'static' figure and started seeing Him as an infinite Source of life, the 'white void' in my head finally started to fill with color. if youre feeling that 'infinite boredom' fear, it might just be that your current picture of the afterlife is too small for how big you were actually made to be.
why Christianity for me? i spent a long time looking for an answer to that 'exit door' feeling in philosophy or just trying to ignore it, but Christianity was the only thing that actually addressed the root of my fear. for me it came down to 3 things.
1: the Nature of God: i realized i was scared because i was picturing a 'static' God who just sat there. but the Bible describes God as a consuming fire, a living water, and a Creator who says "Behold, I am making all things new." (Rev 21:5). Christianity taught me that i wasnt heading toward a 'white void' but toward the Source of all color, sound, and life. u cant get bored of the person who invented the concept of 'newness'!
2: the 'New Earth' promise: i used to think Heaven was, kinda like i said before, an infinite playground with swingsets and stuff to play with which is insanely boring but Christianity promises a New Earth. a physical, tangible reality where we have work to do, things to build, and a whole universe to explore without the weight of sin or exhaustion. we wont ever get bored, because theres always something something totally new and beautiful. its not an escape from reality, its finally entering the real reality.
3: the relationship: with 'The Good Place', it was lonely because it was about people trying to satisfy themselves. Christianity changed the goal for me. its not about living forever, its about being with Someone. when youre truly in love or with your best friend, u arent looking at ur watch wondering when itll end. you're just home! finding God was like finally finding the person i never want to say goodbye to.
i hope this helped you. i believe God helped me outta here and im tryna help the people that i see that are in the same boat i was once in out too, because i care about you and i love you, whoever is reading this.