strange problems with b450 steel legend and crucia

Greetings to the entire forum and I will explain my problem and computer specifications.
asrock b450 steel legend motherboard
amd ryzen 3700x
xfx 570 gpu
blue ray rw pioneer
2 sata drives WD 1000gb
psu be quiet 700w.
And now I'm going to explain the problem to you.
the pc was working perfectly with a crucial p2 nvme drive as boot drive (250gb).
I purchased a new 500GB Crucial P3 Plus hard drive after checking the Crucial compatibility page.
result:bios does not recognize crucial p3 plus disk in m2_1 slot.
The disk is recognized by the BIOS if it is placed in the M2_2 slot, after activating the forced to detect M2_2 option in the BIOS.
It obviously only reaches a ridiculous speed for its specs.
sent to seller and replaced with a crucial p3 disk (I thought the problem was the disk generation of the crucial P3 plus).
the same thing happens.
I have tested the stable bios 4.60 and the latest beta bios available.
the result is the same, i have disabled csm, changed the battery, restored the bios to default values.. without results.
I have opened a support ticket with Asrock Europe and they have replied that they are in contact with the BIOS department waiting to obtain an mvne drive similar to mine this year.
I am waiting for a solution although I think the disk is incompatible for some reason.
Curiously, I bought an identical NVME drive in July for another of my Asrock B450 Pro4 motherboards, it works correctly on it, but when I install this new Crucial P3 it does not start and is not recognized in the BIOS.
That is why I wanted to ask some questions to the most experienced users on the subject.
If the disk was defective it would not work in any of the m2 slots, right?
If the motherboard slot was defective, it would not recognize any M2 disk, right?
Crucial's technical service is totally useless in its responses and does not offer a coherent explanation for what is happening.
Perhaps the rumor circulating on the internet that Crucial has changed the components of its MVME SSDs for lower quality ones that may cause these problems is true?
I would appreciate any comments, ideas or suggestions, because I also can't find an nmve ssd with a competitive price and that really ensures that it works on my motherboard.
thanks in advance

thanks for the reply.

I had already read this post earlier this week, however the list has been updated today, as the fantastic AsRock team has informed me, the Crucial service has only offered me silence as a response and later they have informed me that they will raise the question to the technicians...
The guys at AsRock have obtained two units of Crucial P3 and P3 plus for their tests and have come to the following conclusion:After checking, Crucial has changed their SSD design to PIN73 empty.
So, the problem about Crucial P3 series has been turned into PIN73 empty case.
This causes the drive to not be detected at all.
You need to enable ?œForce M.2_2 to PCIE??to use this SSD in M2_2 slot (but with less PCIE lanes)
I can confirm this, the drive runs at around 1.5gb/s.
Or need an PCIE to M2 adpater card and use it in PCIE4 slot. Keep in mind, M2_1 cannot be used at same time.
I have not tried this option, I have simply returned the mvne drive, it is not an option for me since I intended to use it as a drive for the operating system.
To sum up the situation: I understand that Asrock does not have enough time to test all the mvne units on all their motherboards and I understand that their assessments are based on customer feedback.
What I don't understand is that Crucial specifies on its website regarding product compatibility that the motherboard is compatible with its Crucial P3 and P3 Plus MVNE drives, because it shows that they have not tested the hardware combination.
To cite an example that I am currently using, the mvne P2 units are fully compatible, reliable and very fast, however they do not appear on the official AsRock compatibility list for the B450 steel legend model, however they work perfectly.
In my humble opinion, the manufacturers of NVMe drives have unilaterally changed the connection standard and this causes slightly older motherboards to not recognize this new configuration.
This is a shame, because we have to settle for nvme units from unknown or unreliable brands because the major storage product brands have abandoned us and in the case of finding a storage unit from these brands, the price is outrageous.
For my part, right now I'm using an Intenso brand NVME drive (yes, I know, it's a cheap drive that only reaches 2.4gb/s and may not last long) but at least I have a compatible drive.

in response to your questions:
1 "Force M.2_2 to PCIE"is available in bios 4,60 and later.
2.i used atto to meassure and obtained 1.5 Gb/s near to the teorical limit in specs (16 Gb/s) using only 2 lanes.
I understand its a great perfomance but when you saw a crucial P2 reachin 3.5 Gb/s in M2_1 its reaaly dissapointed to see that.

It is assumed that when you pay a respectable amount of money in relation GB/??or G/dollar for an mvme ssd, you expect the maximum possible result.
Curiously, I have installed a Crucial P3 since July on a B450M Pro motherboard, it works without problems and reaches 32 Gb/s or even a little more.
That was the result I was hoping for but unfortunately the B450 Steel Legend is special for these upgrades.

Right now I'm using a cheap nmve disk (around 30??intense premium), it works in the M2_1 port with read speeds of 24 Gb/s and 19 Gb/s... respectable in my opinion

Thank you. Glad you found a solution. Your speed is much better than with SATA.