Sending sqlite databases to the users which they can interact with using both sql and a viewer is where it's at.
Other options might be SQL Server Express or SQL Server Express LocalDB, the latter of which seems conceptually very much like SQLite within the MS ecosystem, and both of which are usable for production purposes at no cost within the technical limitations that differentiate them from paid editions.
We are not front-end people, so the app is built with the expectation that people will be doing their filtering, searching and using the intelligence we provide, but in their home turf (excel).
Our app also lets users "track" certain events, and we do not use push notifications, rather we respect our user's attention and email them a short summary, and link to a csv that they can use!
(I actually worked for one of such "better off as an .xls file" startup in the past, and its main competitor was an incumbent that sold the same stuff as an Excel extension. Trying to replace that with a React app is not a worthwhile use of life.)
Algorithms are fine. I'll happily apply the most advanced ones I can get. The problem is with who applies them to what - as you and GP said, it's about user control - or, currently, lack of.