Hello, i have a use case, to read from s3 then write to iceberg(on s3), in addition to that i want to create rocksdb state and savepoint/checkpoint for the same when job finish. so that i can start from savepoint/checkpoint for another job, this is warmup/backfill phase then i will start the job to read from kafka once backfill is done then checkpointing is quite easy any thoughts?

Have you checked the Hybrid source? https://nightlies.apache.org/flink/flink-docs-master/docs/connectors/datastream/hybridsource/