convert imag (JPG, PNG) to vector (SVG)

You can perform this conversion by using the DocumentConverter class in the applications back-end service. This has a built in OCR engine which you'll need to leverage since you are wanting to convert to a Vector based image. The ability to extract the text from the original file allows this converison to happen. Here is an example which shows how you can convert to SVG:

using (DocumentConverter documentConverter = new DocumentConverter())         
{         
   var input = @"C:\Input\input.png"); // supports both JPG and PNG 
   var output = @"C:\Output\output.svg");         
   var jobData = DocumentConverterJobs.CreateJobData(input, output, DocumentFormat.Svg);         
   jobData.JobName = "Convert to Svg";         
        
   var documentWriter = new DocumentWriter();         
   documentConverter.SetDocumentWriterInstance(documentWriter);         
        
   var renderingEngine = new AnnWinFormsRenderingEngine();         
   documentConverter.SetAnnRenderingEngineInstance(renderingEngine);         
        
   var job = documentConverter.Jobs.CreateJob(jobData);         
   documentConverter.Jobs.RunJob(job);         
} 

https://www.leadtools.com/help/sdk/tutorials/dotnet-console-convert-files-with-the-document-converter.html