Currently due to business obligations I daven in a minyan with just a minyan of ten. I am the eleventh. 8 of them, including the rabbi, wear the tefillin shel rosh on their foreheads. I spoke to them (including rabbi-who shrugged) and the members - all answer - this is the way to wear it. Several don’t care where they place teffilin shel yad. Their Rabbi does not correct anything. I think (assumption on my part) if he says something they will stop coming altogether. Am i permitted to daven in such a minyan, where people display blatant disregard for the mitzvah of teffilin. I can find another minyan just a bit difficult.

The fact that people place tefillin on the wrong place should not prevent you from praying with them and fulfilling the obligation of Tefillah BeTzibur. If in your understanding it is done out of disrespect for Halacha, you should go pray in another Minyan with G-d-fearing members who observe Halacha properly.