Hello designnerd and welcome to Apple Support Communities.
I see you are having issues with a 3rd party keyboard and mouse when working in Safari on a Mac. This may be related to wireless interference.
Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support
You can also help isolate the cause of the issue by testing using either the onboard keyboard and trackpad (if this is a laptop) or the wired or wireless keyboard that came with the Mac if this is a desktop device.
If the issue is not present when using one of the above devices, try going to System Preferences > Bluetooth. Place the cursor above each device and then click the X on the right to remove the device. Once that's done try shutting everything down and rebooting and then re-pairing each device. Important note: Before taking this step have a wired keyboard and mouse available so that you can access System Preferences > Bluetooth in order to re-pair the devices.
Cheers.