In the U.S. (if you’re in the U.S.), one option is to get allergy shots. And likely other places, but I can’t speak to that.

They do an allergy panel to determine what you’re allergic to and approximately how badly you’re allergic to each thing , then give you injections (usually weekly) of very low, but increasing amounts of the allergens until they feel your reactivity has ceased or decreased to an acceptable level.

I’ve had them. They’re sort of miserable, but they are effective.
They’re miserable because you have to go to the allergist every week, and sit there after the shot until they feel comfortable that you’re not going to have an anaphylactic reaction. But you do have a reaction, and it varies. My average reaction was to spend the next day and a half feeling a bit like I had a cold - sniffles, headache, body aches, and lethargy.
It did, however, ease my allergies significantly.