What pointing devices can be used with iPadOS 13? For reasons that are beyond incomprehensible to me, Apple is not supporting Apple pointing devices for use with iPadOS 13.  Nor are they providing a list of supported devices.  I spent a great deal of time trying to get my trackpad to work before discovering the fine print that Apple won't even support its own hardware. 

Googling 'bluetooth pointing devices compatible with ipad' does not yield any useful results.  

How can I know what to buy without wasting immense time and money through trial and error?

Update: I am not asking how to enable the feature.  That is readily available in the search results.
I have used multiple Logitech Bluetooth mice and they have all seemed to work just fine (my daily driver is the MX Vertical).

I do believe any generic bluetooth mouse works just fine (and by generic i mean it at least has a scroll wheel, 2 buttons and a laser at the bottom)