OnChain NFT metadata (not json) structure, tokenURI is not showing up on OpenSea

Smart Contracts
,
1

I am struggling with NFT On Chain metadata structure. It is not a json file. The contract works fine, the only problem is that the attributes are not visible in OpenSea.

This is the structure I use:

Metadata memory currentId = attributes[_tokenId];
    
  return string(abi.encodePacked(
              'data:application/json;base64,', Base64.encode(bytes(abi.encodePacked(
                          '{"name":"',
                          currentId.name, 
                          '", "description":"',
                          currentId.description,
                          '", "unique ID":"',
                          currentId.uniqueId,
                          '", "color value":"',
                          currentId.colorH,currentId.colorS,currentId.colorL,  
                          '", "image":"',
                          'data:image/svg+xml;base64,',
                          buildImage(_tokenId),
                          '"}')))));

tokenURI:

{"name":"Token 1", "description":"Token description", "unique ID":"6800704", "color value":"2306464", "image":"data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTAyNCIgaGVpZ2h0PSI2MzYiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyI+PGZpbHRlciBoZWlnaHQ9IjIwMCUiIHdpZHRoPSIyMDAlIiB5PSItNTAlIiB4PSItNTAlIiBpZD0ic3ZnXzdfYmx1ciI+PGZlR2F1c3NpYW5CbHVyIHN0ZERldmlhdGlvbj0iMTAiIGluPSJTb3VyY2VHcmFwaGljIi8+PC9maWx0ZXI+PHBhdGggaWQ9InN2Z184IiBkPSJtNTEyLDQwMGMtNDQuNzUxMzgsMCAtODEsLTM2LjY5NjEzIC04MSwtODJjMCwtNDUuMzAzODcgMzYuMjQ4NjIsLTgyIDgxLC04MmM0NC43NTEzOCwwIDgxLDM2LjY5NjEzIDgxLDgyYzAsNDUuMzAzODcgLTM2LjI0ODYyLDgyIC04MSw4MnoiIG9wYWNpdHk9IjEiIHN0cm9rZS13aWR0aD0iNCIgc3Ryb2tlPSJoc2woMjMwLDY0JSw2NCUpIiBmaWxsPSJoc2woMjMwLDY0JSw2NCUpIi8+PHBhdGggZmlsdGVyPSJ1cmwoI3N2Z183X2JsdXIpIiBpZD0ic3ZnXzciIGQ9Im00MzguNTAwMDEsMzA0YzAsLTM0LjI1NDE1IDMyLjg5MjI3LC02MiA3My41LC02MmM0MC42MDc3MywwIDczLjUsMjcuNzQ1ODUgNzMuNSw2MmwtMTQ3LDB6IiBvcGFjaXR5PSIwLjI1IiBzdHJva2Utd2lkdGg9IjAiIGZpbGw9IiNmZmZmZmYiIHN0cm9rZT0iIzAwN2YwMCIvPjx0ZXh0IHN0eWxlPSJjdXJzb3I6IG1vdmU7IiBzdHJva2U9IiMwMDAiIHhtbDpzcGFjZT0icHJlc2VydmUiIHRleHQtYW5jaG9yPSJzdGFydCIgZm9udC1zaXplPSIxMSIgaWQ9InN2Z185IiB5PSI2MDkuNjAwMDEiIHg9IjAiIHN0cm9rZS13aWR0aD0iMCIgZmlsbD0iIzY2NjY2NiI+VG9rZW4gSUQ6MTwvdGV4dD48dGV4dCBzdHJva2U9IiMwMDAiIHhtbDpzcGFjZT0icHJlc2VydmUiIHRleHQtYW5jaG9yPSJzdGFydCIgZm9udC1zaXplPSIxMSIgaWQ9InN2Z18xIiB5PSI2MjEuNiIgeD0iMCIgc3Ryb2tlLXdpZHRoPSIwIiBmaWxsPSIjNjY2NjY2Ij5VbmlxdWUgSUQ6NjgwMDcwNDwvdGV4dD48dGV4dCBzdHlsZT0iY3Vyc29yOiBtb3ZlOyIgc3Ryb2tlPSIjMDAwIiB4bWw6c3BhY2U9InByZXNlcnZlIiB0ZXh0LWFuY2hvcj0ic3RhcnQiIGZvbnQtc2l6ZT0iMTEiIGlkPSJzdmdfMiIgeT0iNjMzLjYwMDA1IiB4PSIwIiBzdHJva2Utd2lkdGg9IjAiIGZpbGw9IiM2NjY2NjYiPkNvbG9yIFZhbHVlOjIzMDY0NjQ8L3RleHQ+PC9zdmc+"}

OpenSea reads the Name and the description but I can't get the attributes to be seen (Unique ID and Color value).
This is not seen even though the tokenURI is there

Screenshot_4
Screenshot_4750×317 24.9 KB

What am I missing? Thank you

2

Attributes must be wrapped in an attributes key:
"attributes": [...]