In the last couple of months my partner and myself quit our jobs to work on that. I am pretty sure that in a year from now the world is going to have a fairly competent spreadsheet alternative.
My capacity is fairly limited but I am trying to build a community around it. Join us!
From libre office because it is web first and also an engine first
It's written in Rust and has bindings to different languages. It's extremely light and fast
I find in software the more constraints I can find the better the innovation ends up being, and business model is an excellent constraint - even just knowing what a responsible amount of effort is versus the value you anticipate.
Admittedly, I originally misunderstood your product as being more like google sheets - where it becomes a cloud drive of sorts with spreadsheets on top. At which point the risk of losing access to the tool would make adoption very unlikely.