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<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 06-April-2024 [03:07:02] {AM}-->
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<link:linkbaseRef xlink:type="simple" xlink:href="dh-20231231_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" />
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<import namespace="http://xbrl.sec.gov/dei/2023" schemaLocation="https://xbrl.sec.gov/dei/2023/dei-2023.xsd" />
<import namespace="http://xbrl.sec.gov/dei-sub/2023" schemaLocation="https://xbrl.sec.gov/dei/2023/dei-sub-2023.xsd" />
<import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd" />
<import namespace="http://fasb.org/srt/2023" schemaLocation="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd" />
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<import namespace="http://www.xbrl.org/2006/ref" schemaLocation="http://www.xbrl.org/2006/ref-2006-02-27.xsd" />
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<import namespace="http://fasb.org/srt-roles/2023" schemaLocation="https://xbrl.fasb.org/srt/2023/elts/srt-roles-2023.xsd" />
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