You can recover the config from the pfSense install image as long as the partition is not completely destroyed, it gives you option before you install:
Worst case you can cat the recovered config to the console from there and copy it out into a file.
The OpenVPN option text should probably be renamed. The engine command in OpenVPN isn't required. When it's unset then it automatically selects a device which supports accelerating whatever cipher it's trying to use.
When it's set to a specific engine, it's supposed to prefer that engine but I don't believe it's restricted to only using that engine. Since most things only have 0-1 available usable engine types, that's not so easy to test.
So really the No Hardware Crypto Acceleration line should be Use any available cryptographic hardware device or something along those lines.