Doesn't Dulera also have a steroid in it, as does Symbicort?

Yes, Dulera and Symbicort both have a steroid in it.

Dulera Inhalers contains a combination formoterol and mometasone. Formoterol is a long-acting bronchodilator that relaxes muscles in the airways to improve breathing. Mometasone is a steroid. It prevents the release of substances in the body that cause inflammation.

Dulera is used as a maintenance treatment for asthma in adults and children who are at least 12 years old. This medication is not for use in treating an asthma or bronchospasm attack.

Symbicort contains a combination of budesonide and formoterol. Budesonide is a steroid that reduces inflammation in the body. Formoterol is a bronchodilator that relaxes muscles in the airways to improve breathing.

Symbicort is used to prevent bronchospasm in people with asthma or chronic obstructive pulmonary disease (COPD).

https://www.drugs.com/dulera.html

https://www.drugs.com/symbicort.html