https://www.youtube.com/watch?v=Vu_gOM3ocnI
Most of the benefit if it exists would be between 2666MHz and 3000MHz likely. It gets hard to compare because higher frequency also has a higher CAS LATENCY so if the CL value is relatively lower on the higher frequency is that where more benefit is coming?
Anyway, watch the video which may or may not be representative of what you'll experience. It's probably right since up to 15% seems to be a good guess without knowing the specifics of the game etc.
Also, I would not mess around with extra VOLTAGE (and STRAP etc) if you don't know what you're doing. If you can get a default profile of 3000MHz working stick with that and maybe educate yourself a bit more later... even then don't crank the voltage up much if possible as that can kill the CPU memory controller over time (AFAIK).
For example:
https://www.gamersnexus.net/guides/3251-raven-ridge-soc-voltage-guidelines-how-to-kill-cpu-with-safe-voltage
"From speaking with numerous contacts at motherboard makers, AMD, and XOCers, general advisement on unsafe SOC voltages is that it begins beyond 1.3V. Conventional wisdom (starting with Ryzen) is that 1.2V is a safe SOC voltage, but we’ve been told by some vendors that Raven Ridge CPUs can reasonably take up to 1.3V, but the suggested input number tends to be 1.2V; this is because, again, the user-configured number and the actual voltage aren’t necessarily equal. Going significantly beyond 1.3V for sustained periods, e.g. 1.34, will likely result in degradation of the IMC over time."