Having been in the 3d community for just over a year, I can share some suggestions and thoughts.

1) Bambu Labs X1 Carbon (X1C)

The X1C was my first printer, and now I have two. My research led me to the Bambu X1C as it was the most automated plug and play printer without much hassle. With it's design I could also print with alot more types of filaments. I've been very happy my printer, I got a 2nd a few months later. I have over 400 hours on each printer without any issues. I've printed many 3d parts for the printer to make it last longer and provide a better experience.

You will need a slicer program to go from 3d model to 3d printer. I recommend the Orca Slicer.

https://github.com/SoftFever/OrcaSlicer

2) 3d Design is through 3D Software. Fusion 360(free depending on license), FreeCAD, OpenSCAD

3) Many sites to download models and print. Reach comments as the author may give tips for printing.

    https://www.printables.com/
    https://www.thingiverse.com/
    https://makerworld.com/en/models/categories

4) Filaments

I'd buy a ton of PLA, and test. Then start buying the type you need for the project.

Good luck!