Bitcoin has no opinion on fractional reserve banking. If entrust your assets to someone else, your contract with them can specify what they do with those assets

Bitcoin has no opinion on fractional reserve banking. If entrust your assets to someone else, your contract with them can specify what they do with those assets until you ask for them. If you don’t like that, find someone else to hold your assets who doesn’t ask for those terms, or hold your assets yourself. But then you become responsible for preventing theft and destruction.