As someone who has worked for numerous chaotic software companies over the years and had a couple rounds of burnout:
You can try the quiet quitting thing, combined with things like meditation and distancing yourself from outcomes (e.g. stoic thinking around realizing what you control and don’t control). That might keep you going for a while.
But I’ve personally found that ultimately there is no substitute for quitting a toxic job and taking real time off (at least 3 weeks). Your body and mind have experienced trauma and need rest.
Best of luck, friendo