Yes, Hyperformula is amazing! it's actually the primary reason TinyCld is AGPL vs MIT, doing so was totally worth it in order to be compatible with it's GPL3 license.
Thanks for a good word! Founder of HyperFormula here. HF will go AGPL soon, too
HyperFormula was the key to unlocking the entire spreadsheet, the technical foundation of sparse rendering and multi-user interactions were easy enough with Yjs and and a few other libs, but I was completely stuck on how to support formulas beyond simple SUM and such until I found it.