I read your other thread. In the U.K. - I don’t know where you live - all dentists are able to do root canals, but not every surgery has microscopes. In the last year I have damaged my teeth badly with clenching and grinding due to stress, and have had four root canals. My own dentist did two, and for one she suggested that the roots were so crooked a specialist might be better - she was happy to try and then refer me on if need be, but I decided to go straight to the endo. What my own dentist (who is GREAT) saw as a challenge was run of the mill for him and his mega microscope. The fourth was a re-treatment, also done by him.
Out of interest I asked him about root canals in general. He said he would be happy for any of his friends who were general dentists to do RCT on his front teeth, and said it was “bread and butter” work. He said beyond that, the teeth have more roots, more canals, and can be far more complicated. Endos have a higher success rate with root canals because it’s essentially all they do, plus they have had years of extra training. (I had to borrow money for the treatment from my mum, and said to her it was the difference between a GP cutting off your leg, and a surgeon doing it. That’s extreme, but you get my drift.)
In general, though, I would say a good dentist is someone who listens, is kind and patient, and who doesn’t make you feel rushed (or daft if you get scared or upset). I also think you need to gel with that person so you can trust them. I saw a different person in my surgery while my dentist was on maternity leave, and while I am sure she was very skilled, and great at her job, I just didn’t “click” with her. That was just a checkup though.