Looks like pretty classic underextrusion. Have you measured the filament diameter to see if it’s exactly 1.75mm? Even 0.1mm is enough to start causing problems. It’s prusament so should be good but worth looking! I can see underextrusion problems in more than just the problematic pillar, so worth playing with retraction and perhaps increasing temperature.

There’s a lot out there for Arduino which is a great platform for learning. Arduino is a microcontroller you can use to read button inputs and control LEDs, all the way up to controlling robots and all sorts of things. It’s pretty hands on compared to a lot of pure software stuff and is often sold in starter kits for kids learning. Worth looking into!

Meshmixer is good for exactly that but it’s been a long time since I’ve used the software.