b die is not the best RAM for high frequency and depending on the sticks PCB design being A1, A2, A0 can have an effect on the max frequency.
~4400 is a good goal for frequency with b die and aim for tight timings.
51c is high enough that it can create instability with tighter timings so try keep them under 50c if you can which should be doable by improving airflow.
My b die runs 4000 16-16-16 with ~1.47v you should be able to run them at a similar speed\v.
4266-4400 should run the same timings with more...
Is it Samsung b die or something else?
Exact model of the RAM please.
If it is b die you can safely run ~1.55v with a fan blowing directly over it or up to 1.5v just with good case airflow.
Some run 1.6-1.7v 24\7 but this can require tweaking of other settings to make it safe.
Some of the first DDR4 made Samsung b die was the fastest.
Newer models that were made on smaller processes which made them cheaper per chip and with higher density's which made them cheaper per GB were unfortunately never able to match the performance of the more expensive b die.
If you play one of the few games that drops below 60FPS due to a CPU bottleneck even with the fastest CPU and sees decent gains from high RAM speeds then it can make a bigger difference than upgrading from 12900K to 14900K.
But there is a lot of programs that see little to no difference and for...
Memory speeds over 6400 can bring decent gains to CPU performance for Intel in some programs but it will make no difference to others which fit within the CPU cache.
AMD however may see a drop in performance especially in latency sensitive tasks when going over 6000\6400.
Also keep in mind you...
You can get desktop RAM with higher JEDEC speeds but usually with really loose timings as they are limited by the vdimm.
Most XMP kits start at a low speed for stability and allow you to increase V and performance with XMP.
A lot of laptops don't support XMP so I guess you just see more of one...
It helps to stabilize the memory controller so it applies to all MB.
Up to 1.4Vdimm and a boost to SOC as suggested above is the easiest wway to improve stability with 4 sticks.
It's ok for finding if you have a dead stick but useless for memory controller instability and not great for slightly unstable RAM.
OCCT RAM test and large CPU stress test are good for checking RAM and memory controller stability.
https://www.ocbase.com/download
By tweaking BIOS settings it...
If its 16-19-19 you may be looking at ~0-3% if its 16-16-16 maybe 0-5% in some CPU limited sections of gamepaly.
So if you think that is worth the $ sure but there is other ways to get much bigger gains like 5800X3D or 7800X3D.
As mentioned tweaking the current kit will get you bigger gains than...
What are the timings on the current RAM? for example 3200c14 to 3600c18 would be slower than what you have and 3200c14 can OC to 3600-3800c14.
Going over 3200 will also change something within the CPU that will make it use ~4w more power idle and load which takes a smidge away from the power...
As mentioned 4 sticks of RAM can be hard for Ryzen 3000 but Ryzen 5000 handles it very well if there single rank and can typically do 4000+ without a problem but the IF usually tops out around 3733-3800 1:1.