Comment by efreak

Try indexeddb. Apparently Firefox is faster than Chrome in recent years when it comes to putting items into a database, but my experience with multi-gigabyte databases (the database contains image blobs and metadata for use as a local webapp) is that chrome is far faster than Firefox. I'd rather use Firefox sure to increased indexeddb limits (for mobile devices with limited storage), but it's just that much slower. I have a chrome-based browser installed on my phone just for PWA use.