How to further optimize my website?

I have a website that is almost done, but I'm having a hard time trying to optimize it further. My points are around 70 (Right now my website is hidden from browsers, so I don't know if that affects the score). I'm using PageSpeed Insights, web.dev, and GTMetrix. Any help? Do not mind being rough with your comments.

The website is: marmolescarlosalberto.es

It is not a worldwide website, the focus is just Spain, I suppose that is important to take into account.