SQL Server Always On Node and File Share Majority
Our goal is that if the primary replica server 1 at site A is down, the Always On Availability Group (AG) fails over to the secondary replica server 2 at site A, and if both servers at site A are down, the AG fails over to site B.


Except for a very specific scenario, this will not work. In all other scenarios you'll lose quorum before you'd ever be able to automatically fail over (which requires... quorum).

The best answer would be to have the DR side be manual failover (it could still be synchronous) with the proper documentation on how to force quorum and bring the AG online.

You could also invest more into VMWare and use their technologies but that assumes the infrastructure, licensing, and ability to implement those products for a specific service such as this.