Basic question, requiring advanced answer.

I can address the Ryzen question. All current Ryzen CPUs (Ryzen 7 and Ryzen 5) comes from the same die... they're effectively the same physical CPU just with cheaper models having some resources disabled. These CPUs have two "Core Complexes" (CCXs), with each CCX having 4 cores and 8MB Lvl3 Cache. The "infinity fabric" is the interconnect between these two core complexes. While it is fast, it is relatively slow and high latency. This means that cores on the same CCX can share more data at a lower latency than cores from the opposite CCX.
When Ryzen was reviewed it was shown to have very capable single threaded performance, but for some reason that strong single threaded performance didn't translate to games as we'd expect it to. One of the theories explaining this was that games need high bandwidth between cores and on Ryzen, CPU cores could be left underutilised because they were regularly waiting on data from a core on the opposite CCX.
One solution to this is through game optimisation, getting game developers to code their games such that threads that are depending on one another are assigned to cores on the same CCX. These cores can communicate with oneanother with higher bandwidth and lower latency, improving performance.
The other solution/mediation is in making the infinity fabric run faster. AMD confirmed that the performance of the infinity fabric is tied to RAM speed, so faster ram = faster infinity fabric, which explains why game performance particularly scales so well on Ryzen CPUs with faster RAM.

In terms of your larger question, I don't claim to be an expert on OCing, but remember that "faster is better" is only true when the component you're tweaking wasn't fast enough to begin with. There's no need to make PCIe slots run faster, for example, because a x16 lane PCIe 3.0 slot is plenty fast enough for a GPU in a gaming machine. My understanding is (and again - I'm no expert so someone will correct me if I'm wrong) that raising the base clock doesn't really net performance gains, which makes me question the merits of doing so. I'd also say that from my (somewhat limited) experience, BCLK overclocking is more difficult to stress test and find stability and results in much less graceful failures than simply tweaking a CPU multiplier and core voltage. I was completely stable in Prime95 but would hard-lock or BSD crash in a graphics benchmark with my BCLK OC. A multiplier OC on the CPU, on the otherhand, would simply result in a notification on Prime95 that a core had failed. To fix that, 99% of the time a have a simple choice between raising the voltage and lowering the frequency... simple!

Right - I've never played around with OCing on an FX CPU, and to be honest, I have no idea whether any of the additional components affected by a base clock OC ever actually limit system performance. If they don't (and my understanding is that on all modern Intel platforms they really, really do not), then you'd absolutely be better off with a higher core clock and leaving everything else alone. But yeah - I have no idea about FX CPUs, so I'll leave that for you and others to discuss.