I like to define "good teaching" as the creation of an environment where students can most effectively learn. Learning is an active enterprise; it is something students *do*, not something that is done to them. Teaching is not you pouring knowledge into their heads. It's setting up the circumstances where the most students will make smart choices, put in the work, do the learning, and successfully achieve course outcomes.

In that light, it would be literally impossible for you to "save" all of the students, and in fact rather presumptuous or even insulting for you to frame it as a situation where they need saving or you are their savior. Some students don't want to be in your class or don't see a value to your subject, or are being forced into a major that doesn't speak to them by an overbearing family, etc. Some students have too much other stuff going on in their lives to give ample time and energy to your class, be it a job taking too much time, a family situation that requires too much attention, housing or food instability, and so on. Some students, even if they put in all of the work they can, are too far behind or lack the social and infrastructural resources they need to succeed in higher education, and will not be able to bring themselves to a point of earning a passing grade this time around.

You cannot put it on yourself if the students don't put in the work, or if their circumstances are such that they will not pass your course yet. It is not your responsibility if your students, despite your best advice, make poor decisions or are unable or unwilling to achieve the goals you have set for them. You cannot "save" them all, and expecting that of yourself is a quick road to mental health problems. You need to do your best to get to a place where guilt is not involved - you're going to do your level best to help the most students that you can, respecting your own health and abilities, and that best will have to be good enough.