I had the same experience. My manager refused to see what was in front of him. After I left that jobs, my mental health greatly improved because I no longer had to deal with unrealistic deadlines from my incompetent manager. The next time I run into this situation again, I know not to voice my concerns and just start looking for a new job. There is no point disagreeing because it is alway you that will lose no matter the outcome. People like sweet talkers, not naysayers. Let them find out themselves when the hard way.

P.s. after I left, my manager couldn’t ship anything for 1 full year. It turns out, I was the only one keeping the boat afloat.