If all OP wanted to do was provide downloadable spreadsheets I don’t believe he would have asked the question.
Telling someone to just “use css html and js” is about as helpful as telling someone to “just write code”.
Telling someone to just “use css html and js” is about as helpful as telling someone to “just write code”.
But you and many others picked up on the implicit premise of this request: to make it in a form that ranks highly on search. A form that is monetizable even if it doesn't help as much. To be clear, I realized this too but I still wanted to point out the more helpful way to cut this for-profit gordion knot.
Maximize help instead of monetization and it's suddenly simple. And you can even work on making a JS/CSS web application after the 15 minutes the simple html+files way takes. Maybe someone else will even make it for you using the spreadsheets you put out. That'd save a lot of time and help everyone the same amount.
I also disagree that downloadable HTML files are a good solution here.
Downloading html files and then opening then isn’t really feasible for anyone outside the tech bubble we are in.
(Don't worry I know you're joking).