@Summertime2 in order to get only those files which were submitted in that specific instance of flow submissions please use following logic to get the files:
1. Instead of using "List Files in Folder" action add "Parse JSON" action. Please make sure you have added "Get response details" to top of your flow
In Parse json action, use the File parameter from dynamic content of Get REsponse action and use following schema json
{
"type": "array",
"items": {
"type": "object",
"properties": {
"name": {
"type": "string"
},
"link": {
"type": "string"
},
"id": {
"type": "string"
},
"type": {},
"size": {
"type": "integer"
},
"referenceId": {
"type": "string"
},
"driveId": {
"type": "string"
},
"status": {
"type": "integer"
},
"uploadSessionUrl": {}
},
"required": [
"name",
"link",
"id",
"type",
"size",
"referenceId",
"driveId",
"status",
"uploadSessionUrl"
]
}
}

2. Then add "Get file content" action, select the "id" value from dynamic content of Parse json. Note this will also add Apply to each action around it.

Now add Create File and Append to array variable inside Apply to each action as described in my previous response.
You can remove "List files in folder" and apply to each which was described in previous response.