Well, I understand the economy of having only one product, but I don't know of a do-all.
There are dedicated glues for securing breadboard components, but they might prove expensive. So, do a search for substitutes... There should be various threads, on the subject, on this forum. "Shoo Goo" is pretty tough stuff, but I don't know that it would be acceptable.
Hot glue is not acceptable to use on a PCB, because any heat will soften it.
Look at the marine stores for substitute waterproof sealing/gluing/caulk products. Remember to get something with a UV rating, for your outdoor uses. Otherwise, it will die shortly.
Keeping the tip sealed and storing the stuff in the refrig will help with the product life, but you just aren't going to be able to keep any of it forever, once it has been opened. A smaller quantity is more expensive per unit, but may save you money by having less die/waste.