Not in our plans.
The light on M5Ultra is a bit limited, so unfortunately no other functions we can put on it
XM5 is quite unique in its sound signature. It's ESS detailed and dynamic, while having a warmed up midrange and bass. M5 Ultra is safer choice, but some users love XM5 for its tuning and put it overall as better than M5 Ultra.
Not something I would ever encounter on M5 Ultra.
Might be glitch of the menu, might be good to try to delete Favourites and put it again at the end of the list, if that helps.
Which iPhone are you using and what cable?
M5 Ultra is a big step up from UA5 in the sound quality. Better DAC, better amps, better power management, it leads to better sound.