Geez, that's really hard in so many ways, even without accounting for current conditions.
There's a lot of new personal/social energy-awareness these days (= recent decades really, but constantly growing), including especially awareness of mental health and an unprecedented elevation of meaningful workplace concerns, to say nothing of natural sensitivities and so on.
This is all good, but in order to be good, it has to first surface a lot of easily-transferable, easily-projectable, highly-personal information.
So, that's all out there. Suffering, made clear, made free-er, louder than it was. Otherwise it's legitimately harder to process and eventually overcome.
And that's just one situation going on, amidst everything else.
Personally I found that trying different work-support theories really helps me. This is a hell of a hand-wavy term, but what that means in effect is maybe trying a nootropic developed for Soviet cosmonauts, see if that makes work more interesting in some ways. I got some caffeine toothpicks in my shopping cart. And some "Another Round" (film) type ideas I'd like to take a crack at some time, in a procedural way.
Playing more with work/life balance too, finding a more efficient way to take on problems before they get too monotonous, and then moving on to stuff I like.
My spouse is good at finding new teamwork theories that help her at work as well. She schedules regular training, and those trainings (depending on the topic!) are actually really good at helping people find meaningful comfort or restorative energy in a lot of cases.
We've also found that creating a pocket of joy--to borrow your term, means pushing for what you want.
Otherwise life, people, problems, will keep encroaching. That feeling _is_ dark.
These boundaries come in a lot of forms, but a huge one is expectations. Of myself, by myself. Or of myself, by others. Or of my team members, by others, and so on.
For example, today I took time out to set a boundary. It took me four revisions of two emails, sending drafts back and forth to involved parties before I was ready to send. I started getting a migraine just as I hit "send".
But now I feel great, because I heard back, and that problem will never be a problem again, and I can keep doing what I enjoy doing without the previous interference.
So some things like that can come up. They are depressing in their arrival. But their goings-away can really create new space for rest and appreciation of life.
(This is to say nothing of thousands of other perspectives, from energetic to sensory to creative and so on. Like, a damn good nap or 9 hours of sleep and a hot shower...a newly-installed Linux desktop of an interesting distro...a new release of some favorite software...this all helps)
Well. Just some thoughts. No fixes offered or guaranteed, but just to share, chime in a bit, etc.
I hope it also helped you a bit to write it out.