Yeah, you may be right about the VRM on your motherboard, but it's obviously not affecting it too much. Better cooling will do wonders for Ryzen, especially 2nd gen, and that may be what's holding your 2700X back the most. I ran my 2700X for a while with my Noctua NH-D15 before switching it back to the 7700K and my scores might be a little higher if I was still using it. It kept temps about 5-10°C cooler than the NH-U14S, which still does an admirable job (but that 7700K gets
really hot, so I switched it back).
Side note - I had run R20 yesterday and scored exactly what you did for multi-core, but I don't remember what the single-core score was (and I forgot to check the box to save best score). Somehow, there was already a 2700X result showing up when I ran it both yesterday and this time, but I know that wasn't from me and I don't see it in anyone else's screenshot. I'm wondering if it somehow picked up my previous saved R15 score, converted it (somehow), and displayed it in the results. Strange.
Anyway, yes, I think it will definitely be worth it to tweak your memory. I mean, you have Samsung B-die and that's the fun of having it and half the reason it costs more. I'm definitely no memory expert. It's a lot of trial and error for me, mostly error. I went ahead and attached a screenshot of the memory timings using Ryzen Timing Checker.
View attachment 118317