Asynchronous vs Synchronous Callbacks

I am designing an app that will have multiple callbacks, each querying different tables of a SQL db.

As I am designingg, it will be helpful to understand if the callbacks will update (query the db) synchronously or asynchronously.

Per the docs, for advanced callbacks:

Whether or not these requests are executed in a synchronous or asynchronous manner depends on the specific setup of the Dash back-end server. If it is running in a multi-threaded environment, then all of the callbacks can be executed simultaneously, and they will return values based on their speed of execution. In a single-threaded environment however, callbacks will be executed one at a time in the order they are received by the server.

Given that this is in Python, would that mean by default that I am running a “single-thread environment?”

If asynchronous the the only option, is there a way to use a package like ‘asyncio’ to at least speed up the total time it takes for all callbacks to load?

thank you!!