> Except for a user on a lower specced device that can’t performantly handle filtering and joining on that mass of data in JS code, or perhaps can’t even hold the data in memory.

Just how low-spec and/or how much state-data are we talking about here? I ask only because I am downloading an entire dataset and doing all the logic on the client, and my PC is ancient.

I'm on a computer from 2011 (i7 870 @ 2.9GHz with 16MB of RAM), and the client-side filtering I do, even on a few dozens of thousand of records retrieved from the server, still takes under a second.

On my private app, my prospect list containing maybe 4k records, each pretty substantial (as they include history of engagements/interactions with that client) is faster to sort and filter on the client than it is to download the entire list.

I am usually waiting for 10s while the hefty dataset downloads, but the sorting and filtering happens in under a second. I do not consider that a poor UX.

What mass of data? Can you give me an example of the kind of device and the kind of use case you're talking about?