Laptop concerns, please help ur non techy human

Laptop details: 5yr old FX505dt AMD TUF gaming Ryzen 7 Windows 11, 144hz
GPU: NVIDIA Ge GTX1650
AMD RADEON tm now with amd adrenalin

I needed to upgrade to windows 11 due to work requirements. It’s working fine until i decided to add external monitor. (MSI 144hz) Nag fflicker po sya, then I brought it to an IT tech, removed some irrelevant drivers and updated some drivers. It worked well to his monitor, upon arriving home still experienced the flicker sa monitor ko. Tried changing HDMI cord pero nag fclicker pa din. Tried din po sa monitor ng kapatid ko, nag fflicker pa din. The tech told me na yung 144hz ko s motherboard eh may tama na. Upon switching to 60hz both laptop and external monitor no flicker until I switch from extended to duplicate monitor, nmmatqy sindi yung display.

I need your help, opinion and such po. Sorry di maalam dito. Thnk you