How to scatter jobs over vnodes?

Please share your pbsnodes -aSj and chunk submission line , what job placement string do you use ?

No, there is no time frame, thousands of jobs are submitting within a minute for some usecases.

smp_cluster_dist is deprecated. please check the PBS Pro administrator guide.

Please check:
4.7 Specifying Job Placement in the PBS Professional User Guide https://www.altair.com/pdfs/pbsworks/PBSUserGuide19.2.3.pdf

and use the below node_sort_key
node_sort_key: “ncpus LOW assigned” ALL