Here is one way you could look at it. Note that this assumes that the two given dates will not fall on Saturday or Sunday.
XML
<input>
<range>
<start_date>2023-03-10</start_date>
<end_date>2023-03-14</end_date>
</range>
<range>
<start_date>2023-03-10</start_date>
<end_date>2023-03-15</end_date>
</range>
<range>
<start_date>2023-03-10</start_date>
<end_date>2023-03-16</end_date>
</range>
<range>
<start_date>2023-03-10</start_date>
<end_date>2023-03-17</end_date>
</range>
<range>
<start_date>2023-03-10</start_date>
<end_date>2023-03-20</end_date>
</range>
</input>
XSLT 2.0
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:my="http://www.example.com/my"
exclude-result-prefixes="xs my">
<xsl:output method="xml" version="1.0" encoding="utf-8" indent="yes"/>
<xsl:function name="my:abs-week-number">
<!-- weeks start on Sunday -->
<xsl:param name="date" as="xs:date"/>
<xsl:variable name="rataDie" select="days-from-duration($date - xs:date('0001-01-01')) + 1"/>
<xsl:sequence select="$rataDie idiv 7"/>
</xsl:function>
<xsl:function name="my:workdays-in-range">
<xsl:param name="startDate" as="xs:date"/>
<xsl:param name="endDate" as="xs:date"/>
<!-- total days -->
<xsl:variable name="total-days" select="days-from-duration($endDate - $startDate)"/>
<!-- number of week boundaries (Sat|Sun) in range -->
<xsl:variable name="weekends" select="my:abs-week-number($endDate) - my:abs-week-number($startDate)"/>
<!-- total days minus weekend days -->
<xsl:sequence select="$total-days - 2*$weekends" />
</xsl:function>
<xsl:template match="/input">
<output>
<xsl:for-each select="range">
<workdays start-date="{start_date}" end-date="{end_date}">
<xsl:value-of select="my:workdays-in-range(start_date, end_date)"/>
</workdays>
</xsl:for-each>
</output>
</xsl:template>
</xsl:stylesheet>
Result
<?xml version="1.0" encoding="utf-8"?>
<output>
<workdays start-date="2023-03-10" end-date="2023-03-14">2</workdays>
<workdays start-date="2023-03-10" end-date="2023-03-15">3</workdays>
<workdays start-date="2023-03-10" end-date="2023-03-16">4</workdays>
<workdays start-date="2023-03-10" end-date="2023-03-17">5</workdays>
<workdays start-date="2023-03-10" end-date="2023-03-20">6</workdays>
</output>