Replace text in Word document using .NET Core - .net-core

Question

I have a Word document where I need to replace certain placeholder variables with actual data using .NET Core.
This is the test document that I'm working with. As you can see it currently has two placeholder variables.
The code I have to read a Word document and replace text comes from MSDN using WordprocessingDocument.
await using var stream = new MemoryStream();
stream.Write(template.Blob, 0, template.Blob.Length);
using (var wordDoc = WordprocessingDocument.Open(stream, true))
{
if (wordDoc.MainDocumentPart == null)
{
return null;
}
string docText;
using (var sr = new StreamReader(wordDoc.MainDocumentPart.GetStream()))
{
docText = await sr.ReadToEndAsync();
}
// Test replacing a variable
Regex regexText = new Regex("{{Building_Current_Version}}");
docText = regexText.Replace(docText, "Some Value");
await using (var sw = new StreamWriter(wordDoc.MainDocumentPart.GetStream(FileMode.Create)))
{
await sw.WriteAsync(docText);
}
}
But this doesn't work because the docText output is formatted like this:
<w:r w:rsidR="00287CAD">
<w:rPr>
<w:lang w:val="en-US"/>
</w:rPr>
<w:br/>
<w:t>{{</w:t>
</w:r>
<w:proofErr w:type="spellStart"/>
<w:r w:rsidR="00287CAD">
<w:rPr>
<w:lang w:val="en-US"/>
</w:rPr>
<w:t>Building_Current_Version</w:t>
</w:r>
<w:proofErr w:type="spellEnd"/>
<w:r w:rsidR="00287CAD">
<w:rPr>
<w:lang w:val="en-US"/>
</w:rPr>
<w:t>}}</w:t>
</w:r>
<w:r w:rsidR="00287CAD">
<w:rPr>
<w:lang w:val="en-US"/>
</w:rPr>
<w:br/>
<w:t>{{</w:t>
</w:r>
<w:proofErr w:type="spellStart"/>
<w:r w:rsidR="00287CAD">
<w:rPr>
<w:lang w:val="en-US"/>
</w:rPr>
<w:t>Building_Current_ValidUntil</w:t>
</w:r>
<w:proofErr w:type="spellEnd"/>
<w:r w:rsidR="00287CAD">
<w:rPr>
<w:lang w:val="en-US"/>
</w:rPr>
<w:t>}}</w:t>
</w:r>
For some reason the brackets are placed in separate XML tags. But sometimes it doesn't do this. Sometimes it also breaks a variable up in separate XML tags. I'm not adding any formatting to the texts.
So it seems like a simple string replace doesn't work here... Unless there is a way to tell Word not to break up the variables in separate XML tags?
How can I solve this issue?