Did anyone's severe asthma turn out to be due to autoimmune/genetic conditions? My cortico-dependent asthma is controlling my life.

I'm currently dealing with severe cortico-dependent asthma (stuck on 40 mg of prednisone daily) in my early 20s despite adhering to treatments, having a healthy body mass, a history of frequent exercise, and no comorbidities. My asthma remains uncontrolled (I get short of breath from slowly walking or lying flat, spirometry shows moderate-to-severe obstruction, 8 puffs of Ventolin daily, two recent hospitalisations) despite the high-dose prednisone, a triple-therapy inhaler, Singulair, and Fasenra (the only biologic I have access to, and even then exceptionally so since I have allergic rather than eosinophilic asthma).

Still, it's pretty clear these symptoms and airflow obstruction are due to asthma since bronchodilators help and trying to titrate the prednisone instantly makes everything worse.

I'm not looking for medical advice but for suggestions about testing to make to my allergist. My allergist says I'm their most severe patient and they have no experience with cortico-dependent asthma. They ordered a chest HRCT given my rapid deterioration, which only revealed mild bronchiectasis; they said it was too mild to be causing respiratory symptoms and attributed it to my long-standing (16 years) asthma.

We've also excluded ABPA since I have no anti-Aspergillus IgE, but my total serum IgE is astronomically high (higher than the assay can quantify). I'd like to get tested for AATD at the very least even if the HRCT was basically fine.

I'm just wondering if anyone's severe asthma turned out to be exacerbated by an autoimmune disease or a genetic disease like AATD?