I switched from Windows a few years ago, and I had the hardest time getting used to moving/maximizing/resizing windows on Mac.

Not sure if that’s what you mean, but if so then “Rectangle” solved all my window management problems, so much so I bought the pro version almost immediately.

If you’re talking about MacOS, I’ve been using Maccy for this

Last I checked, Kobo will be better specs (screen, water proofness and connectivity) for the money, and if you’re technical it can be modified very heavily, including pretty easily user expandable storage.

Kindle will have a more seamless Amazon experience and maybe better support.

I have a Kobo Clara HD, and I love it to bits. Warm temperature backlight, and I have installed custom firmware on it which lets me use a different reader app, and run an SSH server on it so I can remotely transfer files etc.