Have you tried exporting from Access to Excel, formatting the data as a table and then saving the file on OneDrive or Dropbox. You can create a connector to your file and select the table to bring in as a datasource. If you are going to use it simply as a lookup table and not make any changes to it, you can bring it in as a Static datasource and use it instead of a collection. The main advantage is that Collect and ClearCollect are not delegatable. But a static datasource can have as many as 15,000 rows, there is no lag in doing lookups on it ,and all powerapps functions are delegatable.
Could you please share a bit more about your issue?
Do you want to import your exported zip file from your Access into your app using Import control?
Further, is there only one XML file within your exported zip file?
Based on the issue that you mentioned, I think you have some misunderstanding on the sample XML data (e.g. PriceList.zip).
Actually, there are two files within the Sample zip file -- data.xml and schema.json. The screenshot as below:
The data.xmlfile stores the source data. The schema.json file is a configuration file, which used to tell PowerApps how to import the data.xml data into an app.
as an alternative solution, I agree with @Drrickryp's thought almost. You could consider take a try to create a Excel file within your OneDrive folder, then copy data from your Access and paste it into the created Excel file (Or you could consider convert your XML data file into a Excel file along with data has been formatted as a Table).
After that, format the data within your Excel file as a Table, then you could create a connection to the Excel file from your app.
More details about creating an app based on Excel file, please check the following article: