How can I optimize my website for improved speed? [closed]

As for my personal projects, I try to have as few plugins as possible. I often go with the Block Theme Creator and ACF, and try to make my own plugins for my precise task when possible (I’ll not reinvent Yoast SEO but could do some registration moderation in admin, for example).
I could read that deleting all unused themes could also be the job while minifying your CSS and javascript will also help.
Having a good hosting provider could do the trick also. Having all tips in the world couldn’t save you from bad hosting.
Don’t forget to add some cache as well, so the user will not have to download all of your websites every time he navigates it.
That’s all I could think of for the moment but I think it’s a good start!