I assume you've gone through all your patches, so they all have the same volume level
That's not going to happen, and shouldn't happen. Different patches, different songs, different places in a song - all require the player to LISTEN and be in constant control of his level and place in the overall balance, whether by how hard he hits the keys, with his volume knob or with a volume pedal. It's the sound guy's job to facilitate this by letting him hear what's happening.
You don't have to write songs. The world doesn't want you to write songs. It would probably prefer it if you didn't. So write songs if you want to. Otherwise, dont. Go fishing instead.