What Franco is trying to say is, OpenSSL became a headache for maintainers after a sudden burst of several critical vulnerabilities . So the apparent long term fix was forking and coming up with LibreSSL .
LibreSSL was forked by OpenBSD developers and is trying to retain compatibility with OpenSSL, but removed unsafe APIs and put a lot of work into hardening the code base. The direct CVE count comparison between the two shows that LibreSSL was indeed safer. You can find a lot of details about why LibreSSL exists on the internet.The only caveat might be speed, operating system support and other optimisation (hardware acceleration). Since it has become super easy we encourage everyone to try and if it works just the same I'd recommend simply sticking with LibreSSL. There is no more "what if", there is only "do".The wiki is not exactly up to date, but shows you that the "vga" or "serial" usb installer images are what you are looking for, depending on whether you have an embedded device or a VGA port:https://wiki.opnsense.org/index.php/Installation_and_Initial_Configuration#OpenSSL_images