Time to be sad about the end of DAI. ...And by the end of DAI, I really mean the period between DAI and Trespasser, as clarified by the codex entries we get re the companions at the start of Trespasser.

The thing with the two year gap is that... it seems like eventually the entire inner circle (other than the advisors) left. Some of them it's a little unclear (Sera doesn't have a "The Last Few Years" codex entry, and while she's pleased to see everyone they all were gone, so it doesn't mean she was away from Skyhold, but if romanced her journal does say it's "been too long" since she's seen Quiz) and a lot of them seem to have been leaving temporarily, but... yeah, looks like the entire inner circle got to go off and do their own thing, while I get the impression Quiz was still stuck in Skyhold. Varric's in Kirkwall, Vivienne's dealing with the Circles (or Divine), Cassandra is hunting down Seekers or looking for Fade rifts depending on whether or not you told her to reform the Seekers (or Divine), Cole seems to be being sent on assignments with the scouts, Bull's off with the Chargers (if he's Ben-Hassrath it's a little unclear whether or not he left Skyhold, but if he's Ben-Hassrath he doesn't really count as a friend all things considered and if he did stay that would honestly make everything worse in the long run), Blackwall's either reconnecting with his men or doing Warden shit (or I believe in Warden custody if either you made him keep up the lie or didn't do his personal quest), Dorian's in Tevinter (although if romanced he's the only one with a clear timeline, since he specifically says he's been gone a month), and Solas obviously isn't around anymore.

I just... I can't help thinking about Quiz, cut off from all their friends and their lover, getting letters from all their friends about how they're getting on with their lives now that Corypheus is dealt with, and they're dying and it's been two years and they're still stuck in Skyhold. It would be so isolating, getting all these letters from people who are clearly enjoying their lives post-Corypheus when Quiz is still in that castle in the Frostbacks. Trespasser gets down to business pretty fast, so the game doesn't really dwell on what things were like during the period between the end of DAI and the start of Trespasser (some of it would presumably canonically be taken up with doing many side quests, but not all of it), but... I don't know. It just must have been lonely, especially if your Quiz doesn't get on super well with some or all of the advisors.