I'm a little more interested in cultivating utility algae, for food or other purposes. Hopefully those, too are not dangerous in a home setup?

Those are utility algae. E.g. Chlorella is grown as a source of protein. You can buy Chlorella protein powder for human consumption, from various suppliers.

Chlorella has also been used as source of oxygen in enclosed spaces.

The other mentioned algae have also been proposed for such uses.

There was a time when it was believed that Chlorella could become a major source of protein, due to its very high content of protein, but eventually it was concluded that modern agriculture ensures that proteins from legumes, e.g. from soy, pea or fava bean, are cheaper, because Chlorella would need an expensive processing to make it easily digestible, by destroying the cell walls, and also high productivity is conditioned by being able to provide excess carbon dioxide in the water.

For food, growing Spirulina (a blue-green alga, a.k.a. cyanobacterium) is easier than growing Chlorella (a green alga with cellulose cell walls), due to simpler post-processing.