This is incredible. Everything you just said was wrong. You can change 90% of your issues with simple preferences, and those that you cant, like split screen, have simple fixes through lightweight apps like Mirror if you really want it to function differently. You just complained that the hammer isnt working when youre using the wrong end.

Apple stores have tutorials for people that have never used their os before, and they are free. Maybe attend one next time before you shit on a product you clearly know nothing about.