It’s also a serious problem because according to many Poskim one is not yotzei saying the Shem Hashem when saying ‘Ado- rather one must say Adoi-
It seems to me that this is not true at all. It is a matter of custom. Ask your rav.
An even worse problem is when people pronounce Hashems Name as Adi-noy, which according to virtually all Poskim is not valid.
Very common unfortunately. Just listen to Chazaras Hashatz. It’s a mitzvah to publicize this.
This is true. See my comments above. There is a sign in the Mirrer Yeshiva (by the coffee area, for some reason) regarding this matter. Over this past Shabbos, I have heard a baal tefilla for Mincha (erev Shabbos) saying the name of Hashem wrong in EVERY bracha of Chazaras Hashatz. In addition, I heard the baal koreh saying it wrong (Mincha on Shabbos), as well as one of the people who received an aliyah saying it wrong in both brachos. Next time, I will bli neder make a point of rebuking those who say it wrong (if I can muster up the courage to do so).