I am very OCD about this.
I understand exactly where you are coming from OP. Like exactly. My name 'lihimsidhe' is exclusive to me. It's a half made up word so every time I sign up to a given platform, that name is mine. I DO have OCD so this is a big deal to me!
Now here's the other layer of OCD to content with: your name doesn't have to match the type of content you make. My name is basically a spirit from Celtic mythology that inspires creative people to great heights and then brings them crashing down to feed of their pain leaving them broken or dead. But on my youtube I review games and movies. And I'm not Irish WHATSOEVER. And soon I'm going to start doing art streams.
JackSepticEye. PewDiePie. Moist Critical. Destiny. Etc. You get the point. Like it's really nice when your name matches up with your content (The Completionist) but you really don't need it to. So think of something that just sounds interesting and makes you happy. F--k could just be your real name or a twist on it. Sky is the limit.
So to be clear your choices are to create a name unique to you OR constant never ending OCD about your split up name. As long as you don't jam a bunch of random numbers in it and it's 3 syllables max, you'll be fine man trust me.