Solicitud NVME support for DELL Optiplex 790

Hello friends of the Forum, I would like to have some help from you since I do not understand much about the Mod Bios for motherboard, I have a Dell optiplex 790 and my motherboard does not have the interface or the M2 port, so I used a PCIe 3.0 adapter x16 to install an nvme SSD in a PCIe version 2.0 slot; The Bios does not recognize it within the priorities of the device to boot the operating system, it only recognizes it as a storage device… could you help me with this? I appreciate your help.
The characteristics of my PC are the following:

DELL Optiplex MT 790 Core i3 2130
Motherboard: DELL inc. OHY9JP A00
Intel Sandy Bridge Q65 chipset
Bios DELL Inc. A22 dated 03/07/2018
PS: It has a TPM 1.2, UEFI and secure boot

I hope you can help me with a solution to the problem I have with my motherboard, dear friends.

Greetings from Paraguay and thank you very much!!!

This is user side work, so follow the guides:
[HowTo] Get full NVMe Support for all Systems with an AMI UEFI BIOS - Special Topics / NVMe Support for old Systems - Win-Raid Forum (level1techs.com)

Install and boot from an NVMe SSD on a Dell OptiPlex 790 or 990 (tachytelic.net)

After mod bios is flashed, return to the 1rst guide
Step 4 - Installation of the OS onto the NVMe SSD

Good luck.