Getting quotes for a new sewer line, what questions should I be asking?

I have a mostly original 1960s home. The washing machine recently dumped water from the drain line into the mud room. This has been a persistent issue that I borrowed time on my snaking the drain. Most recent plumber found roots and mud in the line.

I am getting quotes and I don't really know what to be asking.

I believe all the plumbing is underneath the slab as homes were built back in the day.

Even worse we have a paved patio in the back so a lot of the work will need to break up the patio.

I surmise one quote is to dig to the slab plumbing and then connect to the original cast iron and replace everything else that goes around the home.

Quotes are in the 15-25k range.

Anyone have this work done with a similar mid century ranch home? What did you do and what did you wish you knew?