The specjvm::xml.validation workloads have issues with scalability on the platforms with high vCPU numbers.
On the reported scores level it looks as:
mainline JDK | 1 | 60 | 120 | 180 | 240
xml.validation | 362 | 4210 | 8070 | 11151 | 11998

On the JFR level for 240vCPU run this workload refers to 2 classes that have noticeable 'total blocked time':
com.sun.org.apache.xerces.internal.impl.xpath.regex.RegularExpression$Context
com.sun.org.apache.xerces.internal.impl.xpath.regex.RegularExpression

The max CPU utilization for this run was ~50%. I was failed to reach higher CPU utilization.

The xml.transformation also have scalability issue but it is not so big:
mainline JDK | 1 | 60 | 120 | 180 | 240
xml.transformation | 131 | 2140 | 4250 | 6196 | 7279
The max CPU utilization for the 240vCPU run also was ~50% according to the JFR.