Drain cleaners should be used very sparingly, especially if you have any metal pipes. What happens is they stay in the drain aRM and damage it, causing an eventual leak in the wall, or they drip down the vent stack at the intersection of it and the drain arm. That’s worse, because when the water does start flowing, it doesn’t wash it away, so it stays in the vent stack to corrode it. This is a particularly common mode of failure in houses built in the 50s, and it’s costly to fix because you have to rip out relatively large sections of wall.
Just something to think about.
Meanwhile, a plumber could have inserted a high quality camera to see exactly what was in there, then dealt with it using the bare minimum of force to not wear your pipes excessively. The cost of fixing the clog isn’t necessarily the cost of the fix. It includes the wear you put on your pipes that eventually causes a failure. Maybe your pipes are all great condition pvc and you have nothing to worry about.