Can't boot without the USB

I'm on an iMac 27 inch, late 2015. It has a 2T Fusion Drive.

Anyhow, I was on Monterey, and decided to upgrade to Sequoia.

I was following Mr. Macintosh's tutorial on YouTube, but my problem is that I multi-task too much, and kept missing steps.

I first messed up when I was creating the installer. I ended up having to wipe the USB clean and start again.

I finally got the installer created properly, got Sequoia installed just fine, but then at the end, when you get the pop up asking if you want to install OpenCore to disk, I don't recall seeing a pop up. I'm not sure what happened...oh, now I remember. It froze. Completely.

So, I couldn't do anything. So I did a restart, and tried again. It completely froze again. (this is inside of Sequoia, on my desktop.)

So I started thinking maybe I had too many apps open (I did not do a clean install, I did an upgrade), so I closed every app and tried again.

Third time, things moved fine and I got to the part where you are supposed to select the drive that you are installing OpenCore to. I selected the wrong drive somehow. There were three choices.

When it was time to reboot, I got a question mark (?). Then it booted into Windows on it's own (I have Bootcamp installed on a small partition).

Put the USB back in, rebooted again, this time instead of selecting the large HDD drive, I selected the small SSD drive (I think I'm starting to understand what a Fusion Drive is). Installed OpenCore to that, restarted, and had the same problem.

Put the USB back in, rebooted for the gazillionth time, this time I kept it in and there were like 4 or 5 choices on the boot loader. I picked one that looked right, and am typing this on my computer now.

Sequoia is working fine, root patches installed fine, but I literally cannot boot without the USB. Not sure what to do to fix this.

By the way, I've been using OCLP for years, this is the fourth machine I've used it on, but the first machine where I've made such a big mess.

Thank you in advance for your assistance.