If the B365 chipset doesn't allow RAM overclock, you can't run memory at the 2666MHz the chipset / motherboard actually supports, unless you also have a CPU that supports 2666Mhz RAM natively as well.
The i3 9100F's integrated memory controller (IMC) supports 2400MHz maximum, while the rest of the 9-series, for example the 9400K, 9600K, 9700K, and 9900K has an integrated memory controller that supports a maximum frequency of 2666MHz.
So it makes sense that your motherboard support up to 2666MHz RAM, since it is designed to support Intel 9th Gen, but with that chipset, your CPU's IMC also needs to support 2666MHz RAM, since it can't overclock.
Setting an XMP profile doesn't just speed up your RAM clock, it affects the IMC as well, and you need a Z-series chipset to alter the IMC performance in order to support RAM frequencies above spec.
That is why AsRock referred you to that page, it tells you that the 9100F has a lower memory frequency support than the other 9th Gen CPUs (most of them at least, I haven't managed to look all of them up yet, so there might be other exceptions).