The best thing you can do for long-term storage from a Professor of Food Science at Cal Poly who is also a stoner: put a layer of Saran Wrap over the mouth of the mason jar before sealing the lid and ring or vacuum seal the lid down enough to seat. Place jars in a NON frost-free freezer. I roasted a doobie of some Purple Haze that I put down in September of 2018 and it’s essentially no different. It will degrade over time but that is your best storage method.
If you have a frost free freezer you could get a cheap styrofoam cooler and put your stash in that then in to the freezer. That should insulate the weed from the temp swings a frost-free freezer subjects the contents to.
I also do a bud wash at harvest which removes any mold spores present that can accelerate decay/breakdown of flower. I just leave the Boveda pack in the jar.
Also; don’t use a vacuum bag and just seal flower, unless you are only doing edibles. It makes it unsmokeable IMO. It crushes it into a hard lump.