You should have unique Nameservers
Be sure that each of your domain has different nameservers so Google will not notice that all your domains are associated. If some of your domains share the same nameserver, be sure that the nameserver is from popular hosting companies that use thousands of legit domains.
You should have unique SOA email addresses
Be sure to have different SOA email address for each PBN domains because this is Google’s other way of tracking PBNs.
Do not buy cheap hosts
Most of the popular and cheap PBN hosts have a high percentage of deindexed domains hosted on them.