Macbook Pro 15 inch 2019: will charging from LG 38WK95C-W via USB-C damage/fry the macbook's battery?

I'm assuming the main concern you have is that charging from the LG 38WK95C-W display is going to damage your MacBook Pro in some way.

This is not something you need to worry about. Having a charging source that provides 60W is really akin to using one of the chargers that ship with the 13" versions of the MacBook Pro on a 15" MacBook Pro. The net result is that your MBP will charge slower than it would with the higher watt charger, but this will not cause any damage to the MacBook Pro.

If you're concerned about this (and you really shouldn't be) you can change the cabling you're using to connect to the display so that you're using one of the display's other ports (e.g. it has HDMI) and totally bypass the USB-C port so that power pass-through doesn't occur. Of course, to do this you'll need a USB-C > HDMI adapter.