Using Amazon OpenSearch Service OpenSearch 2.13 (latest) and Logstash OSS docker image logstash/logstash-oss:7.10.2.

I am getting following error:

INFO ] 2024-08-08 09:56:48.184 [Ruby-0-Thread-5: /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/common.rb:40] elasticsearch - Installing elasticsearch template to _template/logstash

[ERROR] 2024-08-08 09:56:48.345 [Ruby-0-Thread-5: /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/common.rb:40] elasticsearch - Failed to install template. {:message=>"Got response code '400' contacting Elasticsearch at URL 'https://vpc-myapps-opensearch-6jdbalhtywxrdcjn7zxupu.us-west-2.es.amazonaws.com:443/_template/logstash'", 
:class=>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::BadResponseCodeError",
:backtrace=>["/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client/manticore_adapter.rb:80:in `perform_request'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:332:in `perform_request_to_url'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:319:in `block in perform_request'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:414:in `with_connection'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:318:in `perform_request'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:326:in `block in put'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client.rb:352:in `template_put'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/http_client.rb:86:in `template_install'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/template_manager.rb:31:in `install'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/template_manager.rb:17:in `install_template'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/common.rb:218:in `install_template'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-output-elasticsearch-10.7.3-java/lib/logstash/outputs/elasticsearch/common.rb:49:in `block in setup_after_successful_connection'"]}

Following is my Logstash output config block:

    output {
      elasticsearch {
        hosts => ["es_endpoint_redacted_for_brevity"]
        ssl => true
        index => "myapps"
        user => "es_username"
        password => "es_password"
      }
    }

I also use filebeat to ingest logs and the version is elastic/filebeat:7.10.1.

Is this about version mismatches? or something w.r.t. some template? Any pointers?