Stuttering possibly caused by HDD

Hi, I am new to the forum (although I have used it a lot in the past to search for information).
It is a very very long story but I will try to summarize it as much as possible.
I bought a pc in June, when I turned it on I saw that it was freezing in google chrome, I thought it could be a configuration / drivers problem, then I downloaded some games that I know should work with my pc, and there I discovered that there was something VERY wrong. 120 to 1/0 fps drops, constant stuttering, etc.
I tried absolutely everything I found on the internet and did all the possible tests, at that moment I thought that the culprit was my motherboard (it was a gigabyte b560m ds3h ac, and I read that it came with the voltage blocked at 65w, so I thought it could be that), I did the tests, and when I tested the network card there were errors everywhere, so I changed it for an asus tuf gaming b560 plus wifi which is much better. On the other hand, the processor also failed with the intel diagnostic utility, so intel changed the processor for another. After these changes (and doing a clean installation of windows) I turned it on and it continues to work the same. so now my suspicions are about the ram, the hdd, and ultimately the psu.
I tested the ram memory with the windows utility and it did not fail, later I will test it with memtest86. Regarding the hdd i used hard disk sentinel, crystak disk info and hd tune, and as for the health of the disk everything seems to be fine.
BUT when I ran the hd tune benchmark the graph was weird, and as I investigated (although I do not fully interpret it either) I discovered that it is not as it should be, the graph does not form a curve and the burst rate is less than the maximum transfer rate. I will attach some images, feel free to ask me for all the information or images that you consider necessary.
one more thing, the games tested are overwatch, genshin impact, valorrant, the forest, TF2, halo master chief c, and I remember that until now.
I played most of these games on my notebook, which also has only one hdd and although the fps were much lower, I did not suffer from these horrible drops, and I had an intel i3 4005u.
note: I thought about testing the wifi network card of this mother but unlike realtek there does not seem to be a diagnostic tool for this (intel wifi 6).
The components of my pc are:
intel i5 11400
asus tuf gaming b560m-plus wifi
crucial ballistix red bulk 2x8gb 3200mhz
hdd wdblue 2tb sata III 5400rpm
psu game pro 550 80+ bronze

Ordinarily the CPUID instruction is read by the BIOS to set the power level.

I suggest a M.2 SSD for the machine which will perk up boot times like mad

what are you using for graphics?