You should enable the debug logs, it is typically done using jsreport configure command, or by adding to the config

"logger": {
    "console": {
      "transport": "console",
      "level": "debug"
    },
    "file": {
      "transport": "file",
      "level": "info",
      "filename": "logs/reporter.log"
    },
    "error": {
      "transport": "file",
      "level": "error",
      "filename": "logs/error.log"
    }
}

However, the 20% CPU doesn't mean your scripts aren't waiting for the database. They still likely do. It can be because of data IO or something else.

Could you elaborate more?
The input data for the prepend operation are the same as for the original template plus additional $pdf property with currently parsed pdf.
Note if you are trying to simplify TOC generation using prepend, you will be able to reach the same result, but without TOC clickable.

Sorry for the late response, still struggling with it?

Yes, this is complicated. What you probably need to do is use pdf utils extension to dynamically concat pdf parts and implement this in a custom script.
Something like this, just writing from the top of my head..

const jsreport = require('jsreport-proxy')
async function afterRender(req, res) {
  for (let item of req.data.parentPortraitMarginItems) {
    const itemRes = await reporter.render({ template: { name: 'templatefortext' } , data: item } })
    res.content = await jsreport.pdfUtils.append(res.content, itemRes.content)
    const imagesRes = await reporter.render({ template: { name: 'templateforimages' } , data: item } })
    res.content = await jsreport.pdfUtils.append(res.content, imagesRes.content)
  }
}

https://jsreport.net/learn/pdf-utils#usage-in-script

Hi, you are using xlsx recipe?
The common problem resolution here is to open the output in excel, make it how you want, save it.
Unzip both original and fixed and compare what is changed in xmls.
When you find out, try to replicate the change in you

The table of contents can be implemented using pdf utils extension in jsreport.

See the documentation
https://jsreport.net/learn/pdf-utils#toc-table-of-contents

And the demo
https://playground.jsreport.net/w/admin/akYBA4rS

Please check the documentation here
https://jsreport.net/learn/browser-client

You should remove the jsreportInit... wrap.

Thank you for the problem report.
Do you use utility or webserver jsreport local startup?
Did you try to use KillRunningJsReportProcesses during init?

var rs = new LocalReporting()
     .UseBinary(JsReportBinary.GetBinary())
     .KillRunningJsReportProcesses()

The chrome suspended state isn't likely a problem. Rather a jsreport port collision.
I wasn't able to replicate the problems with IIS myself, but I hear some complaints that this is sometimes happening. Have you done some specific IIS configuration? Like configured it to use multiple worker processes?

If you have access to the computer with IIS, could you consider running jsreport outside IIS as windows service? Basically almost all of your current code would stay the same, you would just use the jsreport.Client package instead of the jsreport.Local.

Unfortunately, I don't get what is the problem from your description.
Please share a playground workspace demonstrating your issue.
https://playground.jsreport.net/

Handlebars provide 8 attribute with current index in the each iteration.
You can write a custom helper and use current index to calculate the current cell.

<td data-cell-type="formula">=A{{currentCell 8}}</td>

function currentCell(index) {    
    return index + 1
}

See a demo
https://playground.jsreport.net/w/anon/EDql1QWn

Which recipe do you use?

I believe you should write a custom helper like:

function shouldPrintChart(items) {
  return items.length > 0
}

and then use it around the chart declaration

{{#shouldPrintChart myItems}}
...chart
{{/shouldPrintChart }}