Try either brake cleaner or methylated spirits or white spirit to remove the paint. I have just put KDE Plasma over the top of Ubuntu looks and works great, another good video 😁
I've just been given something similar for free. My first Mac. I've installed Linux Mint XFCE 21.3 on it straight away. You don't need a new battery. It is far too heavy to be portable. I've never touched a Mac before. There are only 2 USB ports.