Lead Developer
You can activate all of them if you need them – they won’t slow down your site.
However, if you don’t need some of them, there’s no need to activate them.
If you enable one like Typography and make changes, deactivating it will also deactivate those changes on your site, so it needs to stay activated.
You can definitely have them all activated if you need all of them for something – it won’t cause any issues 🙂