I tested with my Sprint connection here in Seattle. Speedtest showed average of 61Mbps over 4G and I could stream 2160p from YouTube without buffering. Caveats: I didn't drive over long distances and as mentioned earlier, it is entirely dependent upon availability of consistent high bandwidth. Possible? Yes. Problematic? Likely, but we don't know your operating environment.
Edit: Note that this is on my XS Max, not my iPad. 2160p is not supported in the YouTube iPad implementation. That's another wildcard - what is the streaming source?