If it’s a road bike ,I’ve found that no sealant will seal above 60 psi and I’ve tried quite a few
if it sealed the first two puncturers then it is obviously working otherwise that would have been two new tubes or patches
it won’t seal everything bepends a lot on so many variables
This is nonsense.
There are a number of sealants that are excellent. I run pressures of between 70 and 90 psi in 25mm tyres and use Effetto Mariposa Caffelatex, which is very good. There are others Orange and Maxalami are also good, although I don't believe Stans is very good.
No it won't seal everything you need worms/plugs for larger holes.