I guess this is a question more of when does vmware plan to release a version of vmware workstation pro that has official support for windows server 2019?
As a rule, we don't know futures here, but it's probably a safe bet to assume the next major version will have 2019 support if not a dot release before then. Keep in mind 2019 literally *just* came out so not a whole lot of platforms support it officially at this point.