I've tried searching multiple sites for a potential fix for this and figured I'd come straight to the source.

While going about my business with X6-88 in an attempt to max out my affinity with him, I decided to try something with one of the side quests and knew I'd need to not have X6 with me when I did it. So, while in the Institute, I dismissed him, told him to go to Sanctuary Hills, and I teleported out to the other location. After testing my personal theory, I went to Sanctuary Hills to retrieve X6 and found he wasn't there. I waited a few ingame days and one real day to try and see if he was just taking his sweet time to no avail. I returned to the Institute and scoured every piece of navigable land, again to no avail. Growing desperate, I searched every settlement I had available to see if I'd mis-clicked with no success, and lastly checked the area around where X6 is first obtained, again, no dice.

After doing a number of searches across multiple sites, I found a note on the Fallout wiki that says "When commanding X6-88 to travel to a settlement while the player is in the Institute, he may disappear. When using the console to teleport the player to him via the player.moveto command, the player gets teleported to the Institute but X6 does not appear." This matches my own issue, but their suggested fix, that being "To prevent this simply dismiss him outside the Institute," is not exactly viable since the last selectable save prior to X6's disappearance is 5 hours back. To add, I am on Xbox One and therefore do not have the ability to access the console.

I'm not entirely sure on how to proceed, and this has actually brought my entire game to a halt, as I intended to receive X6's companion perk prior to making any big central plot decisions that would otherwise hamper my abilities to do so. If there is a guaranteed fix for this other than "[censored] outta luck" or "go back to the earlier save," I'd love to know it. Otherwise I may simply have to settle for shelving the game long enough for a viable patch to be released.

Thank you for any assistance that can be provided.