You can upgrade - there is even a great blog about the topic:
Open Distro 1.13.2 needs to be upgraded or mitigated for Log4j.
OpenSearch and Open Distro are similar in use, different in construction. Open Distro is a collection of tools and plugins that sit on top of builds of OSS Elasticsearch and Kibana (in your case version 7.10.2). OpenSearch is a fork of OSS Elasticsearch and Kibana (version 7.10.2) paired with an evolution of the tools and plugins used in Open Distro.