The details are better explained in the document you were already initially using https://iceberg.apache.org/docs/latest/spark-configuration/#replacing-the-session-catalog. The previous URL shared was from understanding there was an issue with listing the "glue" catalog that should've been created for Iceberg table's support. Second part of the problem would be actually reading the data from Iceberg table which would be more on having the right JAR file(s) and being present in the Classpath.

At this point I believe it'll be good to check your setup live through a support ticket, if that's not possible please let us know, we'll continue this way, I'll check if I can set up a similar setup and share the steps.