It has gotten cheaper and easier. Printers start around £200 and filament from £10/kg. There are various suppliers for that. It is a big industry now. I need to get some PETG filament that is better for things that will be outside. I have a few things I could use that for.
The design side is a whole other thing. I would expect you need to experiment a bit.
Yeah, I bet the design aspect will be a lot of time and rabbithole-esque burrowing!