My job keeps adding “just one more thing” to my role and I’m starting to lose it

I’ve hit that point where every week my boss hands me some new responsibility that was never in my job description, never comes with extra pay, and always gets framed as “it should only take a minute.” Except it never takes a minute. Now I’m juggling pieces of three different roles, and somehow I’m still expected to finish everything on the same timeline as before. I tried pushing back last week and was told I should be “grateful” they trust me with more. Meanwhile I’m watching coworkers burn out left and right from the same creeping scope expansion. Look, It’s wild how normalized it is for companies to just slowly absorb your free time and energy because it’s cheaper than hiring another human being. I’m trying to figure out my next move here. Has anyone actually managed to set boundaries around this without it blowing up in their face, or is the only real solution to start planning an exit?