[edlinfan]

> Javascript

A quick note: your spreadsheet had better support arbitrary-precision currency math, if it doesn't already. That's table stakes for a spreadsheet.

To answer your real question, I'd suggest doubling down on the sqlite side and taking things in a relational direction. Spreadsheets are good at tracking 1:1 or 1:many relationships, but my spreadsheets inevitably grow in a many:many direction and I find myself wishing for queries and junction tables.

[phonon]

All major spreadsheets use double-precision floating-point throughout. I'm not sure where you got the impression they "support arbitrary-precision currency math".

In fact they even typically truncate or round the last few bits.