I agree with most of what you say, except that it is not a separate point, it’s an allied point and very relevant to, “How do I get my iPhone fixed.”
I live in a small town, there are no authorized Apple repair shops…nearest one is 120 miles away. The battery in my iPhone was dying and bulging the case open as it expanded. I went on-line to see what my options were and watched a detailed YouTube video of the repair process. That allayed most all fears, so I ordered a repair kit.
I’ve never been into an iPhone in my life, I disassembled it, took the screen out, pulled the battery out, installed the new one, replaced the screen and hooked up several connectors, and reassembled the case. It took all of 30 min. first time. Phone fired right up like new and that was two years ago.
Sure, I voided the warranty, but it was an older iPhone 6 and it would have taken a full day of driving back and forth, wasting 35 gallons of gasoline, hunting around to find the location of the authorized repair shops in the city, and being without my phone for several days, as opposed to 30 minutes. I figured I honestly had nothing to loose other than the $30 investment for the repair kit. If I had screwed up I was prepared to buy a newer model.
My advice is don’t give in, stand up, be a bit independent, educate yourself, and if you feel comfortable enough fiddling with a bit of hardware, go for it. It’s not rocket science.