The cipher_list and tls13_cipher_suites options allow you to specify the list of ciphers to be used. For TLS 1.3 ciphers suites, the tls13_cipher_suites option should be used, otherwise the cipher_list option should be used.
Value: one or more cipher suites separated by colons (see possible cipher suites below).
cipher_list example in config file:
cipher_list= AES256-SHA256:AES128-GCM-SHA256:AES256-GCM-SHA384
tls13_cipher_suites example in config file:
tls13_cipher_suites=TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM_SHA256