As for question title, I am wondering if there is any official confirmation that the new commission "Return to Days of Winter" requires the player to have completed the "Telling It How It Is" achievement before unlocking. Other story related requirements are pretty evident but it is not clear if
Mihoyo realized the implications of Viktor leaving permanently for players that did not yet got the achievement, thus rendering it permanently missable for anyone who didn't get it by the time they completed "Return to Days of Winter".