Huh. It still reads fine to me. I was very precise I thought.
Your English is fine and understandable. I just don’t get how an iPhone can behave the way you describe and especially how Apple couldn’t fix it. I’ve used Apple products from the Apple II days and they have the highest quality, the smoothest upgrades of OS, and the most trouble-free operation of any high-tech equipment I use. I used my iPhone 6 Plus for almost seven years and never had an OS upgrade issue. It finally just didn’t have the horsepower to run today’s apps.