My iPad when connected to hotspot uses too much data

Ensure that your iPad, when connecting to your Cellular hotspot, is configured to use Low Data Mode:

Settings > WiFi > [Your Hotspot Name] - tap the “i” icon, then enable Low Data Mode

Use of Low Data Mode minimises data usage by your iPad.

More info here:

Use Low Data Mode on iPhone, iPad and iPod touch – Apple Support

I hope this information and guidance proves to be helpful in resolving (or at least reducing) your issue with excessive data usage.

Connect to a real Wi-Fi router.

Hotspot uses cellular data.

There's noting we can do to help.

Personal Hotspot uses data, period.