Hi @Anonymous ,
You are trying to pass an array value from flow to canvas app, so the "Respond to a Power app or flow" cannot help with this, because this action can only pass text value instead of array value. Please try below flow:

Please add the Response action at the end of your flow:

Guessing we might have the same columns from the Get list output, so, please try copying below code into your "Response Body JSON Schema" Part:
{
"type": "array",
"items": {
"type": "object",
"properties": {
"Name": {
"type": "string"
},
"DisplayName": {
"type": "string"
},
"Type": {
"type": "string"
}
},
"required": [
"Name",
"DisplayName",
"Type"
]
}
}
If flow get errors about this Response action, please copy this part of the output generated by your own "Get list" action firstly:
Inside the value part, there might be more than one records, but please just copy the first one of them, and then surround this record with [ and ] to make sure you are getting an array.

After copying this "array", click this button in "Response" action:

Paste the array and save the flow to have a try.
In canvas app, I create a gallery to display the array and in the button to trigger the flow, please use below code:
Set(flow_array,your_flow_name.Run())
Then you can directly use flow_array as the items of gallery to show all the data.
Best Regards,
Hen Wang