Is data transfer from a Pixel 3a XL possible via USB 3? The Google Pixel 3a XL has a USB C port.

Is it possible to connect it to a computer that only has a USB 3 port to transfer data between the computer and the Pixel 3a XL?
According to GSM arena the Google Pixel 3a has an USB 2.0 type-C connector.

Note that the USB transfer speed is independent of the used USB connector type.

Therefore USB 3.0 is not supported by the Pixel 3a - you can only use USB 2.0 connections for data transfer.