In WildFly 21.0.0, tried to create a simple Oracle XA datasource. Ran (initially) into HAL-1716 but worked around this (updating the XML manually post creation).

At step 4 (XA Properties), there is a default "URL" name/value pair already present which has to be deleted as there doesn't seem to be a way to edit it and "URL" is a required property for Oracle. That said, the pre-supplied URL is for the Oracle OCI driver (URL=jdbc:oracle:oci8:@tc). The sample URL should be for the (standard/tested) Oracle "thin" driver (e.g. URL=jdbc:oracle:thin:@HOST:PORT:SID).