my computer experiences major frame studders and lags when moving tabs around in windowed mode and has glitch effects

this issue is not actually on my computer but my friends who's computer wouldn't let him access this. but anyway i looked everywhere for a solution but all i could find when searching studders and frame lags were for gaming related issues when this issue it persistent throughout the whole of using the computer. whenever a tab is windowed and he moves it around it stutters and lags the whole computer, sometimes the screen displays this screen tearing/glitch looking effect. and when games are running (even very easy to run games like repo) the entire computer lags out. despite the laptop having very decent specs.

Processor 13th Gen Intel(R) Core(TM) i9-13980HX (2.20 GHz) Installed RAM 16.0 GB (15.6 GB usable) System type 64-bit operating system, x64-based processor NVIDIA GeForce RTX 4070 Laptop GPU

the things we tried was, plugging another monitor in (which seemed to fix the glitching shown in the pictures but other issues persisted), we saw to edit display settings on nvidia control panel but the display settings were non existent, we turned off the "smart charging" on the computer thinking power usage was the problem but nothing happened, we changed the monitors refresh rate but that didn't work we are very desperate for help and i really want to emphasis how the gaming aspect shouldn't be focused on as much as the overall lag of the computer since it is a computer meant for school. thank you