breaking up the large container into more manageable portions is a good idea. Depending on the type of bag you might be able to reseal after a few times, but will probably run into issues long term. I tend to break up large shipments of rice or powders into Mylar bags like:

https://www.amazon.com/dp/B09NRZT65T

They fit well in my 5 gallon pail and give me enough headroom to cut open under the sealed section, and have more room for a new seal underneath. Either way if you are worried about the long term storage of the powder I would use some oxygen scavengers to try and limit how much air can leak in even with an older bag.