If you don’t have WiFi but have cell data and hotspot how do you back up phone with iCloud

With a MiFi or similar device, with borrowed Wi-Fi, or with a 5G-capable device and network.

Or locally and not to iCloud, with a Mac or Windows computer and a cable.

You don't.

Meandeartheye wrote:

If you don’t have WiFi but have cell data and hotspot how do I backup phone to iCloud?

You connect to wifi in order to back up to icloud.