On some motherboards, Resizable BAR is disabled by default (ASUS for example). It’s better to have it enabled, as it can not only add FPS but also improve frametimes.
Virtualization is enabled by default as well and on some configurations it can have a negative impact on performance.
The iGPU is also enabled by default. If you’re using a dedicated graphics card, there’s usually no need to have the iGPU enabled or to have an additional iGPU driver installed. Of course, I’m excluding users who actually use their iGPU.
Memory timings can also be poorly configured by default. With some minor tweaking, you can gain 10 FPS and get a smoother experience.
And then there are things like motherboard fan curves, which are often not configured optimally out of the box, and so on.
So yes, I agree that you don’t need to make drastic changes to a BIOS. But saying that there are no BIOS settings, other than EXPO or overclocking, that can affect the sim is simply not correct.