Exactly… that was constantly on my mind. Last time I hired a plumber to fix a leak while I was away, the plumber was incompetent. Did not find the leak (which was in /exposed/ pipework), charged 200 cash and ran with the money. The plumber actually charged 4 times as much as I paid a doctor to make a house call.
Some plumbers can legally buy sulfuric acid for this purpose. So in fact by law I was essentially being forced to hire a plumber, in effect.
My way of thinking is that I’m going to learn something & my tooling costs will be less than a plumber. I’ll “own” the problem for the next time. This one about drove me to the edge, considering I was about to experiment with borderline parasites.
A pro would have had an expensive snake cam… so there’s that. I would not want to put my own snake cam down the pipe because it’s not made for such filthy environments… would likely ruin the cam.
I blame whatever plumber installed the drain. They used many hard-right 90° fittings that hinder snakes. Then they installed no clean-out. And no vent. I also suspect the pipes under the floor may be goffred (accordian-like). So the lesson here is that snakes are not always the answer if the pipes are lousy.