Do you have a large base on single player? Funcom just announced the problems they are having with the Xbox here. It sounds like the console is running out of memory and since it can’t find any it crashes to the home screen. I have the same issue you do when I try to load my main single player save on my original Xbox, but I can load this save without issues on my Xbox One X. A cheap work around (instead of buying a new Xbox One X) is to create a new Xbox user account and start a single player game using the new account. After a couple of minutes, switch users (I would switch using the Xbox menu and not through Conan) to your main Xbox account and then load your multiplayer session. This is the way I play online on my older Xbox.
Hope this helps.