For me, copper sulfate crystals once every six weeks works & has worked for 30 years. If I was working on the road and skipped copper sulfate for a few months, then I have to snake the roots out.
The plumbers at work once tried the foaming stuff from 3 brands in jars with hair line roots in them. Nothing at all dissolved, even after a week. The bigger problem was that if it did not work and someone had to cable the line or handle the water, the water would burn the skin and eyes. It's almost as thoughtless a using Draino then calling a plumber.
For us, treating the disease (repairing the problem) will require about 400 square feet of 6" concrete drive to be removed, so we treat the symptoms.
We bought sewer line insurance and will let them pay when the pipe fails completely. Meanwhile, they snake for free. $60/year peace of mind & I can sell my trusty & reliable Speedroter 90 to someone who will appreciate it.