LLMs are also really good at generating regex based on a short description. It’s saved me a bunch of time, since I don’t use regex often enough to become proficient at it, but it’s necessary for certain particular things (such as find/replace with Notepad++, or hyper-specific URIs in Bitwarden)
Because you don’t have a driveway/hose, I would try something like the Simple Green “OxySolve” cleaning concentrate (it says it’s for power washers but there are mixing instructions for “manual cleaning”). Most concrete cleaners have some pretty harsh chemicals in them that could damage your bathtub, but the Simple Green stuff seems pretty tame.