It's a really hectic week and I may not get a chance for a while to properly announce / blog about this, but FYI I created project https://github.com/bstansberry/deployment-transformer-feature-pack and pushed a 1.0.0.Beta1 release to repository.jboss.org.
Maven GAV for the feature-pack is org.wildfly.deployment:wildfly-deployment-transformer-feature-pack:1.0.0.Beta1.
It lets you install the org.wildfly.deployment.transformation module into standard WildFly 27. That module is what WildFly Preview has been using to transform EE 8 managed deployments to EE 9.1, as discussed in https://docs.wildfly.org/27/WildFly_and_WildFly_Preview.html#wildfly-preview-support-for-ee-8-deployments. This facility *may* allow your EE 8 deployments to run in WF 27, if there is nothing in them that relies on things that were in EE 9.1 but were removed in EE 10.
Best regards,
Brian Stansberry
Project Lead, WildFly