Adapter from 3 wire to smart port?

@Subway_Kid, I understand your frustration.

VEX promised Smart Port sensors and 3-Wire Expander (last section) for the legacy ports long time ago and still hadn’t delivered.

If your V5 Brain with non-functioning legacy ports is still on the warranty you could contact VEX Support and ask for a replacement unit.

If you have all 8 functioning 3-Wire ports, it is not that bad, because you are competing against other VRC teams that have to work with the same limit.

Finally, as the last resort you may try this technique that allows you to connect multiple simple sensors to a single 3-Wire legacy port:

Simple sensors would be digital (one state) switches and buttons.

For example, instead of using potentiometer and line sensor on your tray, you can hook up three limit switches to a single port: two for the end positions of the tray and one for detecting the cubes. This will save you, at least, one port without reducing end functionality.