Super confused about brake bleeding

Hello!

Fair warning I am quite new to cars and car maintenance lol (have lived in nyc most of my life until now), but I have some confusion with brake bleeding.

I recently bought a 2009 Prius with about 188k miles. Unfortunately after about a month a goose like little honking sound started happening when holding on the brakes (and the car is stopped). I understand now that this is the brake actuator. I took it to a shop and they quoted me $3000 for a new ABS pump but they also said they didn't try anything else and simply said the sound was coming from there so I need to replace it (even though there are no dashboard warning lights and they said no internal codes). I then learned that the bleeding procedure is typically the first thing to try and do to fix it first, so I took it to a Japanese specialized mechanic. He said the bleeding on the techstream "failed" and I need still need a new ABS pump (they quoted me $3,700).

I'm now looking into buying a second hand pump and doing the replacement myself (or bringing it back to the japanese auto care place who said they'll install used pumps). But I also have been reading people saying that the techstream sometimes "fails" and a manual bleed is what you should do. But I don't really get the difference or when one is required or not. Is a techstream *technically* required/recommended by toyota anytime you bleed your brakes at all (like when changing brake fluids and needing to flush it out), or is it simply when you need those internal valves flushed out? I also just see so many conflicting things just in these forums about bleeding procedures. Like whether to go into "invalid" mode or "diagnostic mode", whether to have the car on or not, and random other stuff. I believe the risk is the car spamming you with warning lights afterwards?

Sorry for the long post just a bit overwhelmed. I'm new to car maintenance but not maintenance stuff in general and I already have lots of the tools needed so the actually labor doesn't scare me, I just am confused on the correct procedures.

Any help would be great!