Hi!
Recently I did a lot of benchmarks by applying Profile-Guided Optimization (PGO) to different software (including a lot of databases) - the results are available in https://github.com/zamazan4ik/awesome-pgo/.
Also, I did MongoDB benchmarks with PGO - https://github.com/zamazan4ik/awesome-pgo/blob/main/mongodb.md
I think these results will be interesting for the MongoDB community. I hope the MongoDB developers will consider providing a note about PGO and MongoDB somewhere in the documentation, adding a build option to MongoDB for easier PGO builds, preparing PGO-optimized binaries, or even will use PGO internally for cloud-based MongoDB installation.