We are in a remote location with cellular data only (via a WiFi hotspot). The connection is fast, but the cost is high. There seems to be no way to limit the video quality or otherwise reduce data consumption, other than to turn video off. Is that true?
For preserving incoming bandwidth (download) you can stay switched to Active Speaker view and keep your Zoom window scaled down to a small size.
If you are receiving a Screen Share from another participant in Zoom, you are somewhat at their mercy.
You might want to check your Operating System for Metered Connection settings. You may be able to throttle your bandwidth usage there.
Hope this also helps.