Another plumber diagnosed my problem as a broken pipe under the slab and gave me a $20,000.00 estimate to replace all plumbing in both the back to back bathrooms.
I got a second opinion from Honest Bob Frank. Showed him the video from the 1st plumber. He told us without clearing the blockage we couldn't be sure if the pipe was broken or just obstructed.
He came out, cleared the obstruction at the base of the main stack, put his camera on it to confirm, and we are back to draining normally.
Bob Frank was honest, direct and did not jump to conclusions.
He's definitely old school but has all the tools as well. Jetting, camera... all of it.
Big recommendation and Thank You, Bob!