Here is the specification sheet for the Dell Inspiron 14 1459.
https://dl.dell.com/manuals/all-products/esuprt_laptop/esuprt_inspiron_laptop/inspiron-14-5459-lapto...
You state that the graphics card is not detected. Making some assumptions...
- You've disassembled the laptop and verified the discrete graphics card is installed
- You're posting on an AMD forum, which suggests the discrete graphics is AMD based
- Per the above Dell specs, the only AMD card it could be is the Radeon R5 M335
If all of the above is true, based on the screenshot of Windows Device Manager, it seems the card is not functioning, else it would be detected by Windows. Some things to check...
- You are not using Windows 11 - per Dell Windows 11 is not supported on this laptop
- You have downloaded and installed all Dell driver packages for your hardware
- Device Manager indicates other devices flagged with missing drivers
Dell Driver Support for Inspiron 5459
https://www.dell.com/support/product-details/en-us/product/inspiron-14-5459-laptop/drivers
Ryzen R7 5700X | B550 Gaming X | 2x16GB G.Skill 3600 | Radeon RX 7900XT
Ryzen R7 5700G | B550 Gaming X | 2x8GB G.Skill 4000 | Radeon Vega 8 IGP
Ryzen R5 5600 | B550 Gaming Edge | 4x8GB G.Skill 3600 | Radeon RX 6800XT