Game freezes/stutters on mouse movements!

A very annoying problem emerged recently with my laptop. When I run Apex Legends or my brave browser it happens following situation:

When I don’t move my connected USB Mouse (Logitech G402), the game runs fine with 40-45 fps. When I move the cursor in menu or look around in game, the rendered animations stop completely on my screen, but continue as soon as I stop moving my mouse from the point it now should be. Like if there is a clock: It counts, when I move my mouse it will stop the clocks animation at e.g. 00:01:20. If I move my mouse for let’s say 5 sec, it will continue right at 00:06:20, right the moment I stop movement.

Battlefield 4 is working properly (with other bugs, but I’ll guess that’s the game).

When I disconnect my USB mouse, even while the game is running, the problem stops, is not apparent with my laptop inbuilt touchpad. I used a different mouse (Logitech MX anywhere2) to test the problem, and also no problem running the game.

This is odd. It feels like the mouse input brings the RAM or CPU to a complete hold.

Specs and everything: http://speccy.piriform.com/results/ISYh7DWsv3G6Aq5JvMi6dLE

Things I remember doing in the time the game ran fine last time till the problem:

• Updated all Intel, Dell (including newest BIOS), NVidia drivers.
• Bought and connected a second monitor (BenQ GL2580H), connected via HDMI and installed appropriate drivers.

Things I already tried after researching the problem on many forums (and which obviously did not help!):

• Change Mouse tick rate from 1000hz to 500hz or 200hz or 125hz. Deactivate Fusion engine. Deactivate mouse smooth in game and windows.
• Reinstall Logitech game Centre. Deinstalled it and installed G-Suite (crap of a program).
• Clean installed the Nvidia driver. Switched all settings to use the high-performance card instead of Intel HD onboard. (Checked in the task manager, right GPU is used properly.)
• Changed r5apex.exe in the compatibility options to “Deactivate Fullscreen optimization”. Changed via regedit r5apex to be run on “High priority” in the task manager.
• Reinstalled latest BIOS firmware flash. Tried “AC only” and other BIOS power management options. (excluding a battery problem)  
• Tweaked any energy/power options Windows offers for a laptop.
• Unplugged the second screen. Switched windows options on which is the main screen.
• Update Windows version, Microsoft Store apps and verified via Origin Apex multiple times.
• All game overlays are deactivated. Background programs on a bare minimum.
• In Device manager I deinstalled all “Mouse” Hardware and drivers. Reconnected and plugged mouse in again. Disabled “NVidia Audio Device”
• Switched between my 3 given USB 3.0 ports.
• Searched for viruses via Avast and Malwarebytes.