> I'm looking for a way to have a searchable/filterable CSV file of 30k rows as a web app.

Can you expand on this? How would people express the searches and filters? SQL? or some other way?

Assuming SQL, all the work's done for you already! :D A single static page that serves sqlite3-in-wasm to the client browser, with, I donno, A text box to enter SQL queries and a file picker.