Is it medically possible to make a combination sublingual drop for a variety of common allergies without side-effects? $250 for a test and then whatever payment

Is it medically possible to make a combination sublingual drop for a variety of common allergies without side-effects? $250 for a test and then whatever payments to have a doctor prescribe it is out of reach for many. A single over-the-counter for the more common allergies, or even regional over-the-counters for regional allergens, would be reach a lot more people. For the serious allergic reactions I can see why a personalized plan would be required. But for the more mild reactions this seems hypothetically possible. Aside: If wondered for a bit whether something like honey blends of many regional honeys for young children older than 6 months would eliminate most of the seasonal pollen allergies that people develop from moving to other parts of the country/world. Edit to add: I believe you're wrong about the "technically" part. Allergies aren't attacking the body (therefore not "auto"), merely causing symptoms through the general immune response against the allergen. This is particularly aggravating to an individual because the immune response is long lasting, as it's impossible for the immune system to eliminate the foreign antigen when said antigen is prevalent in the environment.