Fair enough not wanting to mess with the CPU but I would recommend giving 'Ryzen DRAM Calculator', made by the same guy, a go.
Download 'Thaiphoon', export a report, pull it into RDC, set a couple of boxes for mobo, ram type etc, hit 'calculate safe', put the numbers in BIOS.
Give me a nudge if you want more in-depth instructions but there's plenty of info on it available.
You only really need to worry about the main page if it looks like too much faff to do the rest.
I got a big uplift in mem perf from doing that over having XMP set, same mem speed but tighter timings at lower voltage.
I did look at that a while back but never really worked for me, but didn't use that thaiphoone thing so will try again. Last time I tried it wouldn't boot after changing timings and had to clear cmos.
As an aside I played about tonight more with the CPU settings having found out I "forgot" to plug in the small 4pin power supply to the CPU, only had the 6pin plugged in!
Long story short I have managed to improve both benchmarks and gaming fps by using a static voltage of 1.250 and setting clocks per ccx. Kind of like how CTR did. But now using the ryzen high performance power plan in windows and these changes I am seeing an actual improvement and lower temps. Finally lol.
I'm a proper clown for missing that 4pin connector lol. Text my mate about it as he got the exact same rig as me (copycat) and he had also missed the same plug too, so made me feel better lol.
I still feel my chip isn't performing as well as it should compare to review benchmarks and what others seem to get, close but not as good, but I'm leaving it now. Probably just silicon lottery.