1)Virus scan the system? Adwcleaner is a good free tool - can find things that usually get past AVs:
https://www.malwarebytes.com/adwcleaner/
2)Run Windows System File Checker:
https://support.microsoft.com/en-us/help/4026529/windows-10-using-system-file-checker
3)Strix Z370 Gaming motherboard drivers:
VGA
Audio
Lan
Chipset: 2019/04/03 Intel Chipset Driver, and 2019/04/04 Management Engine Interface
Sata
Bios: 2019/03/12, Use the included Management Engine Update tool via Asus Setup to update your ME... then 2019/07/18.
4)If you were using a gpu prior to the 2080Ti, was Display Driver Uninstaller used to remove the previous driver, after which you installed the newest recommended driver from Nvidia's site?
[Don't install Geforce Experience, as it auto 'optimizes' in game settings, which aren't always ideal for you.]
5)Hardware Acceleration: I use Firefox, so finding it is as simple as going to the browser options, and scrolling down until I find it.
6)"i cant go higher than 1080p cuz i have a 1080p 240hz monitor"
Nvidia Control Panel > Manage 3D Settings. DSR is greyed out?
7)To check per core usage, you can use:
HWINFO
Intel Extreme Tuning Utility
Msi Afterburner
8)"and my psu is a rm750x corsair white psu"
Ok, you're good there, at least.