As always, my comfort games tend to be low-flow games. I spent a lot of time the last month or two playing Shenzhen IO - but the “comfort” part of it was the Solitaire game (also separately available as Shenzhen Solitaire).
Probably the most consistent comfort game of this year, and last, has been Noita, though - the tempo of its gameplay [and the correctly roguelite level of variation and combination] fits the sweet spot in terms of both the “stress curve” - most of the time Noita is low stress, with peaks of intense stress - and also the “loss curve” - generally, restarting a run of Noita on death isn’t that disappointing [because you’ll discover new things next time]. (As a contrast, Spelunky 2 fails both of these metrics for me, which saddened me, as Spelunky Classic and HD both did.)
I didn’t dip into X-Com [the original - or, nowadays, lets be honest, the Open-source remake OpenXCom] since February, but it’s definitely always installed, as it’s been a comfort game ever since the original game on the Amiga back in 1994.
Pretty much the only flow game that’s still on my list is Super Hexagon - for me, actually achieving flow needs as few inputs as possible, and Super Hexagon has the bare minimum. [Plus, the almost hypnotic tunes by Chipzel really help induce that state.]