You do realise that teachers themselves don't make the policies, right? Teachers are made to implement them, even if they mean that they themselves are screwed! In fact, you might not even realise this, but teachers are observed by the leadership team to ensure that they are checking for planners, equipment, uniform, make up, false eyelashes, false nails, earrings, and a long etc. in addition to having to perform lunchtime/toilet duties, run clubs, do restorative conversations, run homework clubs, go on trips, etc etc. This is all outside actual teaching, league tables, preparing lessons, marking, parents evening, etc.
Most teachers I know have to purchase spare pens and pencils for their students out of their own pocket, only for students to borrow them, because they've forgotten the basics one needs in school, and either kept them, lost them, destroyed them, etc. I have never known a student to forget their mobile phone, yet they seem to forget pens, homework, books, rulers, etc on a regular basis.
Students rocking up even a couple of minutes late to their lessons is extremely disruptive to everyone. It is not feasible for a teacher to try and get to the bottom of each student's difficulties. Parents need to start accepting the responsibility of bringing children into this word. Schools are not responsible for everything. And don't even get me started on mental health, and how much parents expect schools not just to do their parenting, but also fix their childrens' mental health.