Windows 10 ending support just means that you won't get updates. Your Windows 10 installation won't vanish instantly. Keeping Windows is when you change your mind or have a problem with your Linux installation, to have a backup system.

That's a good. You may still keep Windows on the side to use just in case. And you may use Linux all the time until you get really used to it. Then you may totally remove it sometime. I advise you to keep it until you're really sure.

God gave you ass holes, so it's your duty taking shits as much possible. with this mindset

Depends on your needs. If you use any proprietary production tools like Photoshop, you may still need to keep Windows on the side. As for myself, unless the user really gets used to Linux, gains some experience, I do not advise to switch to Linux fully. I've seen so many people who did this and returned back to Windows.