When Google unveiled the list of devices that will support the beta version of its next-generation operating system Android Q, it was notable that the brand new Pixel 3a and Pixel 3a XL smartphones weren't on the list of eligible devices. However, it appears that this is just a temporary glitch and both devices will eligible for the beta from next month.
https://www.notebookcheck.net/Pixel-3a-3a-XL-won-t-be-enrolled-in-Android-Q-beta-program-till-next-month.420504.0.html