Hello, and welcome!
I agree with IdOp - experiment, learn, and above all
research before making an investment.
Keep in mind, each BSD is a unique OS. These are not "distributions" of a shared kernel as with Linux. You may discover that only one of them has something you require. But if the hardware you believe would be needed is not supported, there may be alternative solutions.
As an example, you stated a desire for 802.11ac. This is not possible with OpenBSD, yet. But that does not stop you from deploying an 802.11ac bridge on a subnet that is
protected by OpenBSD.
So don't just do a feature comparison with a checklist. Design a solution. This is where laboratory testing can be very helpful. You can prove the validity of the design and components before investing in any new hardware.
Old hardware, spare hardware, and virtual machines can all be part of a testing (and education) regimen.
