foofer, I feel your pain.
I also have had a rough time with tubeless.
Something I don't see in these conversations - what if you have offset rims? My sole experience with tubeless has been with our Bontrager offset rims. Because of the offset profile, the valve stem nut only contacts the rim on one side.
I bought the official Bontrager tubeless kits for our bikes (wife and me). Goop, valve stems, and thick plastic rim strip. The Bontrager rim strips have a little recess that's supposed to hold the valve stem in place but the recess is shallow and the valve stem will pop out of the recess with little effort. A person can try pushing from the back during installation but because of the offset rim and poor contact with the valve stem nut it all seems shaky. I tried double-nutting the valve stem but no matter what I did the valve stem would leak air with just a nudge of a finger. Not confidence-inspiring.