low time and low effort huh. put it into your investment portfolio. are you on track for maxing out your roth ira this year? should probably start there if you're in usa. etf's, mutual funds, DCA into crypto.. all things you can be looking into for something truly passive and takes less than an hour to configure.
everything else that is not directly related to putting money into your existing business will take substantial effort you do not wish to part with.
search "how do i invest" or "what would you do with" on the search bar... 1000 of threads identical this. honestly i do not think the OPs gain any insight. nobodys throwing 10k...20k..100k on a 1-liner reply that they couldn't have thought of themselves spending 30 minutes on the forum. don't look for shortcuts that do not exist