Chain selects search?

I generally don’t reach out here but I figured I would give it a try.

While I know I can make the first drop down of a chain select searchable, is there a way to hide the list of results during the search?

For instance I am using chain select for zip code/rate tax and the dataset is large over 42000 records. I have succeeded in this however, it is very slow (using wpdatatables) and takes a few seconds to 5-6 seconds to load. (Sluggish).

Preferably I would like to have the default zip code populate based on the user that is logged in (populate anything) about to pay an invoice.

I have the chain working where if you search for the zip code and select it, it pulls the correct rate into the tax field and calculates correctly.

If anyone has any suggestions on the best way to tweak this to work where the zip auto pops and checks the chain (or another way, faster?) for the correct rate without the user having the ability to change the zip code in anyway?

Thanks in advance for any input:)

Ken