You can use StartsWith("Server") to filter out the required object, then throw in another split on "=" and "/", probably easier with RegEx, but I like splits e.g.:
$string = "Provider=SQLOLEDB;Server=PCNameSQL_Instance;SomeOtherCrap=moreWords;ThisGoes=OnAndOn"
$string.Split(";") | Where {$_.startswith("Server")}
Server=PCNameSQL_Instance
($string.Split(";") | Where {$_.startswith("Server")}).split("=")[1].split("")[0]
PCName
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