I mean, there's two sides to this. On the one hand, gratitude that things could suck more shouldn't be used as an excuse to not make them better. But on the other, one of the basic tenets of Stoicism is the idea of negative visualization. Humans are extremely adaptable and can be happy in a multitude of circumstances, and focusing on all the good things you still have definitely does make a shitty situation more bearable. It's not an alternative to making things better, it's in addition.
I have to say that as much as I value stoicism, in the context of burnout, I completely disagree with this.
Everyone has an adaptive capacity and burnout is what happens when people exceed that adaptive capacity. It's what happens when they hit the limit of what they can psychologically and physiologically take and just keep taking it.
If someone is burning out, they have to proactively change *something*. Seek therapy, learn better boundaries, change their work environment, something.
I think stoicism is great *IF* you aren't actively engaging in a lifestyle that is damaging your health and well being. That's like employing stoicism to adapt to the discomfort of alcoholism so that you can put off quitting. It makes no sense.
Humans are adaptable, sure, but there's also no denying that the vast majority of people in our society are not adapting all that well. They're physically unhealthy and overwhelmingly suffering from mental health struggles. So when the current social pressures are predominantly making people sick, it's worth challenging them.
That's where the concept of gratitude gets perverted. If people's priorities are already set in a way that will injure them, then the things they feel they should be grateful for will also follow that damaged programming.
So they'll be in a job that they don't strictly need, their mental health will be declining, their physical health will be declining, their basic self care lapsing, their relationships suffering, and they'll continue to tell themselves they should be grateful for it because their paycheque is bigger than someone else's, or because their employer isn't as abusive as the last one.
If someone's priorities are set so that they're willing to choose to obliterate their own well being, then stoicism and gratitude and anything else that keeps them stagnating isn't helpful.