Here’s my therapy experience, in case it answers some of your questions:

I've had three therapists in my life.

The first one, when I was 15, was amazing. I was first treated as an inpatient at a clinic, and when I was discharged, they told me I should continue outpatient therapy with her. She was amazing because she seemed to really care about me, we had great, insightful conversations, and she gave me homework like writing down my thoughts (they basically turned into a book, lol). But when I needed therapy again, I couldn’t go back to her because I was now an adult.

But since I was in university at the time, I had access to student support services. After the first conversation, they gave me a list of numbers, and I called each one until someone was able to give me an appointment relatively soon.

However, I really didn’t like that second therapist because he suggested some wild solutions, like sleeping with my best friend to stop being a virgin, which he seemed to think was my main issue, lol. He was still nice, and it wasn’t entirely wrong to suggest it. Given what I told him about our friendship, it made sense to bring it up, but it bothered me that he kept mentioning it even after I told him several times that I didn’t think it was a good idea and that it made me feel uncomfortable to talk about her like that.

When I realized our conversations weren’t going anywhere, I simply stopped showing up and realized I needed to figure myself out on my own. So instead of switching, I just felt like it was a huge waste of time, and I wasn’t looking forward to telling someone the whole story again anyway. Learning that I had to carry myself, and that therapy is just a way to keep my thoughts from getting even worse (like putting a lower bound on them), but not necessarily a way to make them better, was a worthwhile lesson though. YMMV though.

Then, after a few years, I again felt like I needed someone to talk to. I think I looked up phone numbers myself and it was again mostly random how I got matched with someone.

That experience was also not good. I didn't feel like she knew what she was doing. Our conversations were too mechanical. So I again felt like it was a huge waste of time. I think thanks to my past experiences with therapy, I could basically predict what she's going to ask, so I thought:

When she was sick and referred me to someone else for the week, I just didn't make a new appointment.

So I would say if you talked to them for at least four hours and you don't feel like they have told you anything that really made you think deeply, you should maybe find someone else. The "chemistry" is also important.