I bought my first seeds from Mephisto back in early 2020 I think it was. I've had them stored in a container, with rice to absorb any rogue moisture. I just planted some of them in my most recent grow and they popped within 48 hours. And they seem to continue growing like you'd expect them to.
Everything I've read, and I think you're already seeing anecdotal evidence, as long as you properly store them and that environment doesnt change too often and stays stable(this seems the most important) then they should be good for many years. I certainly am not scared of them not germing(yet). and haven't seen too many people giving reason to be concerned.
fwiw, I don't do anything accept put them I a solution, wait until they get to a point where I can push it and it's no longer as buoyant, perhaps not sinking but not coming back up either. Then I put them in to e little peat pod, germ to seedling then move the peat pod in to the bucket I intend to grow in and away we go.