This can be from stuff like RGB software running in the background. Best case you reinstall Windows and install nothing but chipset drivers and video drivers and install valorant, nothing else, no other programs at all. If still issues it could be compatibility issue somewhere, hardware or software.

Unfortunately windows will automatically install tings like razer synapse and it's pretty hard to get it to not do that, you have to fully uninstall those things bd ausejist closing then leaves them running in the background, typically as services you could stop but it's better to just uninstall that stuff completely. Never install Asus armory crate, you have to find a special uninstaller on asuses website just to have a chance of actually removing it, it leaves a ton of remnants behind if you just use the build in uninstaller and they could cause issues like this.