A very nice article explaining how to migrate from an external Platform Service Controller to an embedded one:

https://blogs.vmware.com/vsphere/2019/02/understanding-the-vcenter-server-converge-tool.html

A note about versioning: use the same version of the converge tool as the version of your vCenter and PSC. Otherwise the converge will most likely fail (as it did when using 6.7 tool on a 6.5 environment).