You choose to have an alt. If you don't want to do the work that multiple character have then don't choose to do it. It is always silly when people complain about the choice they make to have multiple characters. 70-105 per quest is still an average of 770 to 1,115 a day for on average an hour of work (that includes travel time). You also complain about getting a boost when 75% done while excluding all the vendor stuff. Which that boost obviously helps obtain faster after investing in the sanctum upgrades.
It isn't a grind to be expected to do 11 quests a day in about an hour of play time. If you did that you would have all sanctum upgrades unlocked and be working on the cosmetics. But sure it is wild to expect people to play the game that they choose to spend time with. If that concept is so wild why not just quit?