It looks like [SSL://10.221.0.93:19090,SSL://10.221.0.93:19091,SSL://10.221.0.93:19092] is not even accessible, check if the broker is up and its port opened.

Try use options https://github.com/confluentinc/librdkafka/wiki/Using-SSL-with-librdkafka

Java-based variant of options

My additional properties:

security.protocol=SSL
ssl.truststore.location=/home/pasha/@Projects/@DATA/kafka.scripts/conf/DEV/truststore.jks
ssl.truststore.password=********
ssl.keystore.location=/home/pasha/@Projects/@DATA/kafka.scripts/conf/DEV/keystore.jks
ssl.keystore.password=********

That works for the confluent utilities, but for plumber I've got in logs:

[2023-05-27 19:07:32.045] [error] AdminClient[fd7060cd-3a43d3cd] failed to be initialized with property[ssl.truststore.location:/home/pasha/@Projects/@DATA/kafka.scripts/conf/DEV/truststore.jks], result[-1]
[2023-05-27 19:07:32.045] [error] AdminClient[fd7060cd-3a43d3cd] failed to be initialized with property[ssl.truststore.password:izkAChIbjEV4ZWN2], result[-2]
[2023-05-27 19:07:32.100] [error] Unexpected exception caught: 2023-05-27 19:07:32.100775: Local: Invalid argument or configuration [-186] (/home/dmitriy/develop/plumber/3rdparty/modern-cpp-kafka/include/kafka/KafkaClient.h:429)

Kcat based variant (librdpkafka based)

I've tried also variant which works for the kcat:

ssl.ca.location=/home/pasha/@Projects/@DATA/kafka.scripts/conf/DEV/truststore.cer.pem
ssl.certificate.location=/home/pasha/@Projects/@DATA/kafka.scripts/conf/DEV/keystore.pem
ssl.key.location=/home/pasha/@Projects/@DATA/kafka.scripts/conf/DEV/newrsakeystore.pem
security.protocol=SSL

But got error:

[2023-05-27 19:13:49.373] [error] AdminClient[d6d15608-1a4031d4] FAIL | [thrd:ssl://10.221.0.93:19090/bootstrap]: ssl://10.221.0.93:19090/bootstrap: SSL handshake failed: error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed: broker certificate could not be verified, verify that ssl.ca.location is correctly configured or root CA certificates are installed (install ca-certificates package) (after 25ms in state SSL_HANDSHAKE)
[2023-05-27 19:13:50.377] [error] AdminClient[d6d15608-1a4031d4] FAIL | [thrd:ssl://10.221.0.93:19091/bootstrap]: ssl://10.221.0.93:19091/bootstrap: SSL handshake failed: error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed: broker certificate could not be verified, verify that ssl.ca.location is correctly configured or root CA certificates are installed (install ca-certificates package) (after 21ms in state SSL_HANDSHAKE)
[2023-05-27 19:13:51.413] [error] AdminClient[d6d15608-1a4031d4] FAIL | [thrd:ssl://10.221.0.93:19092/bootstrap]: ssl://10.221.0.93:19092/bootstrap: SSL handshake failed: error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed: broker certificate could not be verified, verify that ssl.ca.location is correctly configured or root CA certificates are installed (install ca-certificates package) (after 19ms in state SSL_HANDSHAKE)
[2023-05-27 19:13:51.413] [error] AdminClient[d6d15608-1a4031d4] ERROR | [thrd:ssl://10.221.0.93:19092/bootstrap]: 3/3 brokers are down
[2023-05-27 19:13:51.416] [error] AdminClient[d6d15608-1a4031d4] FAIL | [thrd:ssl://10.221.0.93:19091/bootstrap]: ssl://10.221.0.93:19091/bootstrap: SSL handshake failed: error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed: broker certificate could not be verified, verify that ssl.ca.location is correctly configured or root CA certificates are installed (install ca-certificates package) (after 16ms in state SSL_HANDSHAKE, 1 identical error(s) suppressed)
[2023-05-27 19:13:52.532] [error] AdminClient[d6d15608-1a4031d4] FAIL | [thrd:ssl://10.221.0.93:19092/bootstrap]: ssl://10.221.0.93:19092/bootstrap: SSL handshake failed: error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed: broker certificate could not be verified, verify that ssl.ca.location is correctly configured or root CA certificates are installed (install ca-certificates package) (after 14ms in state SSL_HANDSHAKE, 1 identical error(s) suppressed)
[2023-05-27 19:13:54.368] [error] AdminClient[d6d15608-1a4031d4] FAIL | [thrd:ssl://10.221.0.93:19090/bootstrap]: ssl://10.221.0.93:19090/bootstrap: SSL handshake failed: error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed: broker certificate could not be verified, verify that ssl.ca.location is correctly configured or root CA certificates are installed (install ca-certificates package) (after 20ms in state SSL_HANDSHAKE, 1 identical error(s) suppressed)