I posted letters from R’ Elya Ber and R’ Yisroel Kalmanovitch, but they are in the distinct minority of people who have publicly encouraged people to daven, and R’ Yisroel was referring specifically to Eretz Yisroel which is a different story. I haven’t seen anything of the sort from anyone else. Also, R’ Elya Ber did write in the letter that you must follow proper safety protocols. Presumably high risk people should also not be attending, but I wouldn’t necessarily assume anything from it.
Link?
Discounting the one letter that you say is referring to EY, which we all agree is a totally different situation (though IMHO potentially more dangerous), that's a far cry from "hundreds of Rabbonim, likely many from their hometowns, strongly urging people to make yard minyanim".
As I pointed out, a posek takes into account many considerations. I believe that considering the inequality of the situation, where some are able to hold minyanim based on a certain standard, while others are simply not lucky enough to have that option (והמסתעף מכל הנ"ל), was a major factor in guidance given by many Rabbonim.