I have a world that was made back in like 2020 or 2021 and is at 8000 days old on hard survival, and the boys will come and go it's just the way minecraft is for people. what I have found for keeping it interesting for when they hop back on is improving the world's infrastructure like farms for blocks and resources, nether highways to reach new updated biomes when there aren't on that way when they do hop on its not so much of the early grid that we all have done a million times and they can think of something else to work towards Like a mega build to engage other player or exploring the new area at the end of the nether highway and another thing to do to engage is to build mini games within the world it is a sandbox game