Cold Take: They should've given Custom Partner Future Gohan Potential Unleashed or SSJ2 as a reference to him getting them in one of the Alternative Timelines in Shiny Budokai : r/dbxv
DRAGON BALL XENOVERSE 2 | Official Website (EN)
Training For The Future ! Mentor Future Gohan - Dragon Ball Xenoverse 2 - YouTube
Xenoverse 2 All Gohan & Videl Mentor Quotes Infinite History DLC (Eng) - YouTube