Just moved to a mac and I'm having the same experience you had. Never had issues with Windows or various Linux distros. Currently I have a pretty absurd Karabiner config to work around some of the issues but I still haven't ironed them all out.

Home/End always worked for me on Windows and didn't work for me on mac until I did a ton of tweaking.

Same for me. Home start of line. Ctrl + Home is start of document.

My Dell laptop has Fn keys on the left/right arrow that do home/end in the same way it sounds like Macs do.