I am reading more about OS development on other websites and found out about Unreal Mode, where you switch to protected mode, load a new GDT, and switch back to real mode, so you can use Real Mode benefits without the penalty of the little amount of ram.
My OS design does not use normal binary files, and instead uses a bytecode system read by the kernel (Similar to how Java works) so I do not have to worry about malicious programs with a sneaky CLI or HLT in the code.
With my design, is Unreal Mode still safe or should I continue using Protected Mode?
For BIOS functions, "real mode" is a relatively insignificant problem (it's fairly easy to solve using a variety of methods).
For all the problems that actually do matter, see this warning
You should not use BIOS functions; and if you aren't using BIOS functions then you have no reason to prefer (e.g.) Unreal Mode over Protected Mode.