I've received feedback from staff with colour-blindness who feel alignment can be challenging because they can't differentiate between red and green. The colour of the lines is important when aligning: https://docs.rws.com/en-US/sdl-trados-studio-783545/color-codes-and-tooltips-for-alignment-connections-341583
I haven't been able to find a way of customising the colours of the lines - View > Colour Scheme doesn't affect them, and neither does any of the configurations under File > Options > Colors.
Please enable this.