About mongodb $search Function & "text" index perfomance

I’m Korean use English is not good. Please understand.

Now, I’m using mongoDB 4.0.10.

In one Collection has “text” index for $search value.

value is Only String, that creating by Korean, Chinese, Japanese, English.

but Query speed is not fast. most 2s, 1.6s, 3s.

I want use other way for $search, but I cant find better way for $search.

can you tell me good way for $search or find??