Hi @Anonymous ,
Based on the issue that you mentioned, I think there is something wrong with your flow's configuration.
Currently, within MS Flow (Power Automate), it could only accept text string parameter passed from a canvas app. Passing an array value from a canvas app into a flow directly is not supported within PowerApps and MS Flow.
As an alternative solution, you should convert the table value into a JSON String value within your app firstly, then pass the converted JSON String value as parameter into your flow, then within your flow, you could use the json function (WDL expression) to convert the passed JSON string value into a JSON Table again, then typed the JSON Table (array data) into the "Tabelle" field of the "Populate a Microsoft Word template" action.
On your side, you should re-configure your flow as below:

Add a "Compose" action before the "Populate a Microsoft Word template" action in your flow, then type in "Ask in PowerApps" dynamic content within the "Inputs" field. (The "Compose" action is used to receive JSON String value passed from your app)
Then within your "Populate a Microsoft Word template" action, set the "Tabelle" field to following formula:
json(triggerBody()['Compose_Inputs'])
Within your app, you should convert the Table value (you want to pass to flow) into a JSON String value firstly, then use the converted JSON String value as argument within the 'FlowName'.Run(...) formula to pass to your flow:
The table value I want to pass from app to flow looks like below:

The app's configuration as below:

More details about the JSON function in PowerApps, please check the following article:
JSON function
Please also check and see if the following thread would help in your scenario:
https://powerusers.microsoft.com/t5/Building-Power-Apps-Formerly/Capture-Image-and-Save-as-Attachment/m-p/360072
Best regards,