I use homemade or a quality pre-made stock if I can, but I don't stress about it. If a cube or stock pot is all I have, or time for, then that's what I use.
I got to know a Michelin star chef, we had an enlightening conversation when he told me he uses shop bought, ready made crushed garlic for convenience when cooking at home. I thought how ironic that was, lots of home cooks wouldn't dream of doing that and instead would be busy making it fresh from cloves - yet here we have a top chef using it.
A book on traditional Italian cooking methods I have says to only use water for fish risottos (or risotti!), I use a light chicken stock most of the time.
Adding a few knobs of butter and grated Parmesan at the end helps to create the creamy texture. Just add them and let them melt before combining.
Yes, you can make frozen stock pots using an ice cube tray or freeze the stock in portions.
Good luck with your risotto!
I use diced and crushed garlic from jars, because I can get really good Central-California garlic that way. The fresh garlic in the store is imported from another part of the world, and doesn't have the full garlic flavor of the California garlic I buy in a jar. I use canned tomatoes for the exact same reason.
As for stock, I don't have room to store homemade stock in my freezer. I want a second freezer, but for now, I use a product called Better Than Bouillon, which is a paste that works like a stock cube.
BTW, do you use the famous Grimsby smoked haddock?