I see. So it's not mandatory to do. So I can work at it at my pace and still join in the Ultimate Quests and Extreme UQ and not worry about making the group fail.
Character in question is a 79/75 Hu/Su, Fury Wire Lance build with Alternate Wired Lance and Enhance Crit Chance rings. Currently I have a Nemesis Lance +35 with Might III, Stam III and Cast III (currently trying to replace these) with 11* units all enhanced to +10 and Extension level 8, 5, 5. Units all have Might II, Stam II. Going for lots of health, hopefully lots of defence and damage. Units are still a work in progress, but currently focusing on augmenting my Nemesis Lance as I feel I will have this weapon for a long time yet.
With this kind of build, I seem to do pretty good in Ultimate Quests and rarely get taken down. So I can continue augmenting at a pace I find acceptable and not feel like I am being carried is what I'm understanding from the replies so far. That is good to know. Perhaps I'll start joining those difficulties more often.