I'm the same, all of the knock off's don't taste very good. Mostly it seems they have much more vinegar flavor which I don't like and is most of the time the main reason why I think they are inferior.
Have you tried Sriraja Panich Sriracha?[1] It's one of the many sauces that claims to be the original Thai version. I liked the taste pretty well, just as much as the version manufactured here although they are different. It doesn't taste anything like Sriracha but I prefer Bachan's BBQ Sauce to Sriracha. [2]
Yes, to me this is a Coke like product. There are other sriracha sauces, just like there's other cola drinks, but so far there's only one Huy Fong Sriracha.
True though it's in the substantial economic interest of house brand teams to make it good enough, so they will keep trying. TJ in particular is quite good at this.
Trader Joe's incredible ability to pull this off in general, and inability to replicate Huy Fong (at least, last I tried) is a big part of what convinces me that Huy Fong must be doing something really special in how they make their sauce.
I haven't done a side by side with it, but the red dragon sauce is damn good.
Maybe a bit different than Huy Fong, but it checks the box for me.
Side note, the main mechanism TJs and other store brands use to pull off this trick is to have the original manufacturers produce the product for them as a white label product.
It remains a differentiated product based on its core feature, taste.