If you want to format multiple JSON files into one CSV for NTFS on OpenSea, you can try Data File Converter, just in a few mouse clicks.
1. Open Data File Converter, select “Files” – “JSON”, “File” – “CSV”.
2. Choose OpenSea JSON metadata files folder.
Config JSON options.
Custom JSON columns.
3. Set CSV options.
4. “Next” and “Next”, convert, get the output CSV file, like this:
name,description,external_url,image,properties/files,properties/category,properties/creators,compiler,attributes[Background],attributes[Luckbox]
1,,,1.png,"[{"uri":"1.png","type":"image/png"}]",image,[],NFTexport.io,BLAU3,4
2,,,2.png,"[{"uri":"2.png","type":"image/png"}]",image,[],NFTexport.io,BLAU2,1
3,,,3.png,"[{"uri":"3.png","type":"image/png"}]",image,[],NFTexport.io,DOT-8,1
4,,,4.png,"[{"uri":"4.png","type":"image/png"}]",image,[],NFTexport.io,HYBRID3,1
5,,,5.png,"[{"uri":"5.png","type":"image/png"}]",image,[],NFTexport.io,DOT-6,3
6,,,6.png,"[{"uri":"6.png","type":"image/png"}]",image,[],NFTexport.io,NOT WHITE 1,1
7,,,7.png,"[{"uri":"7.png","type":"image/png"}]",image,[],NFTexport.io,DOT-8,4
8,,,8.png,"[{"uri":"8.png","type":"image/png"}]",image,[],NFTexport.io,NOT WHITE 3,3
9,,,9.png,"[{"uri":"9.png","type":"image/png"}]",image,[],NFTexport.io,DOT-1,4
10,,,10.png,"[{"uri":"10.png","type":"image/png"}]",image,[],NFTexport.io,HYBRID3,5
...