Huge perf drops seen on MongoDB v5.0 vs v4.2.1

we notice Huge perf drops seen on MongoDB v5.0 vs v4.2.1

we are using a community benchmarking tool called YCSB . can you help us craft a benchmarking config for MongoDB that represents realistic workload generator, database size, instance sizes.

can you suggest a tool that can be used to collect profiling data like how mongo uses hardware for various tests, and do you have any tool that can be leveraged for Performance benchmarking?