Open core EFI disappeared

Context:

I had been running Sonoma (using OCLP) on MacBook Pro 15” (late 2016) for about 6 months now, without any issues.

I also had Windows 10 as a guest OS running on Virtualbox (with macOS) as the host - no issues.

I recently installed Windows 11 as a guest OS on virtualbox. Everything was fine, until I restarted my Mac.

Now I get the “forbidden” symbol on Mac startup, and when I use the “option” button to bring up the boot options, I don’t see the OCLP EFI (just the mac EFI)

Has anyone faced this, or can explain as to what happened?

Do I need to reinstall Sonoma via OCLP (using a USB)? Will that wipe my data?

How do I prevent this from happening going forward, assuming I also want to operate Windows 11 on Virtualbox.