Is the KDF pbkdf2 included in the openssl suite?
LibreSSL enc docs: https://man.openbsd.org/openssl.1#ENC

OpenSSL enc docs for version 1.1.1 : https://www.openssl.org/docs/man1.1.1/man1/enc.html

Both support pbkdf2. I am kinda surprised LibreSSL still supports DES, I would not support it. Can you paste the exact error you're getting?

Edit:

The changelog of libressl says pbkdf2 support was added in version 2.9.1 (latest current version).

Comparing the openssl 1.1.1 man page above with the openssl 1.1.0 enc man page, I see pbkdf2 support was added in version 1.1.1 (latest current stable version).

You're trying to use a very new feature.