Hi,
I sorry, I am still confused sorry. You keep saying "Table" in SharePoint. Which means an Excel file with a Table in a file that you store in SharePoint(aka master file), but I thought you wanted them in a SharePoint List?
So I am still going to assume you do NOT need a master file, because you are always writing the incoming file to a SharePoint List, NOT a single (master) file.
Here is what it looks like now
Step 1. Trigger Email Arrives
Step 2. loop through attachments (Apply to each condition) using Attachments from Trigger
Step 3. use a Condition to validate that the Attachment file name is the xlsx you want (or you can use a pattern, or you can put a filter on the Trigger for the attachment as well). I put this here for teaching too
Step 4. Once you find the attachment, write it to SharePoint (you can delete it later if you want)
Step 5. Use the Create Table to make the required table in the file
Step 6. List the rows in the Table
Step 7. Create an Apply to each to LOOP through the values in Step 6 using value (dynamic property)
Step 8. Use Get Items to "validate" if a Row exists or NOT in SharePoint list already
Step 9. Use a condition to validate that there was 1 row. You use the length(against the Step 8 body array length)
Step 10a. No Condition, do a Create Item into List as its a new row
Step 10b. Yes Condition, do an Update item based on the ID you get from Get Items array. Remember there is only 1 row, so you dont need to LOOP you can use Array notation etc to get the Row/record in Step 8 directly. You COULD use an Apply to each to loop but its a single loop.

Cheers
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Thank You
Michael Gernaey MCT | MCSE | MCP | Self-Contractor| Ex-Microsoft
https://gernaeysoftware.com
LinkedIn: https://www.linkedin.com/in/michaelgernaey