Mouse lags when cursor is on an external display and not the built in MacBook Pro display

I have a 2019 MacBook Pro (the one with the 4 USB-C ports only) and an LG 4K HDR WQHD Display. I tried using an HDMI cable with a USB-C hub to connect them. However this results in a severe lag when the mouse cursor is on the external display. When the mouse is on the native MacBook Pro screen, there's no lag.

I figured it must be an outdated HDMI cable or something, so I purchased a new USB-C to HDMI cable. This doesn't work at all - just results in a blank screen on the LG. I tried all of the ports on the MacBook Pro.

So what in the world do I need to do to use an external monitor with a MacBook Pro (without mouse lag/latency)? This shouldn't be that hard.

Any links to specific cables or adapters that work for sure are appreciated.

Edit: Perhaps due to refresh rate mismatch? There's no option to change the LG to 60 Hz (which is the max offered on the MacBook Pro display). The LG seems to only offer 75 Hz as a refresh rate.

So there's no way to make these two products work together?

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.