Come on, a 'FAANG engineer' asking for help with this is like a gourmet chef asking for help boiling an egg. It's pretty much the most basic stuff imaginable, kids are learning this in pre-school pretty much.

Op writes his request like he wants to help people. Doing it the simple html and files download way would help people quite a bit and very quickly. After all, it's the way he choses to do it, so it must be pretty good. It has all those properties he asked for and people don't even have to depend on a third party staying up.

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.