Right now I'm using a shoebox with jars and ziplock bags, each with silica gel, inside a normal side by side fridge.
I recently decided to test my methods by popping some seeds from back in 2011/2012 and they're still super viable. Hopefully this continues.
I had a thought that I would upgrade the shoebox to a plastic ammo storage case like:
https://www.amazon.com/gp/product/B01CNP4HMG
I'd line the bottom with sheet gel packs which can be cut and shaped:
https://www.amazon.com/gp/product/B07DQGSWYY
And cover that with a sheet of plastic and tape in the bottom 1 inch or so of the case.
Then I'll keep the case in the fridge. If the power ever goes out, or the fridge has problems, then maybe there will be some extra hours of cold protection with those gel packs. It would also make for easy/safe transport if I have to take it somewhere in a hurry. My seeds are probably one of the first things I want to grab if I have to bug out quickly. I have lost my whole collection before, in the mid 2000's. I still kick myself a lot... though not as much these days since I have so much great stuff to work with now. (A little under 2000 seeds)