This one works well in my home (20 lb. tank to Drinkmate): https://www.amazon.com/gp/product/B08B4KLMVZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Of course I have no way of knowing for sure, but what you describe is likely the result of the nut that attaches to the Drinkmate being loose. Do you think that if you took a wrench to it you might be able to tighten it just a little more?

FWIW, I run mine with a 10-lb tank that's open all the time. I use this connector. It seems every adapter out there has reviews where people describe the hissing you noted, including this one. I had the issue too, but just had to tighten the connection a little more.