You sure can. But maybe it just needs a bit more work. So don't be too hasty.

Hi yes you can. However I'd save the content I have created, you can do that in site content if not done so already.

You can change anything in your site except the URL.

I agree that starting from scratch is a good idea. But if you want to keep the original domain name, you could do that also. Just delete all the original content. The second time around should be much easier. You have learned a lot to get where you are in your journey. You will see as you continue to move forward, the path is a little clearer than before.

Hi. What's wrong with it? You can start as many websites as you like, well there's a limit, but of course you could start all over. My advice would be to start a second one, choose a different domain name, but keep the other one and look at it later when you have gained new aspiration. Good luck.