Just don’t use school property for things you want to be private. It works the exact same way with anything owned by any organization you may work for in the future.
Why would you not separate personal devices from school devices? If you can afford a personal device, do so; it won’t be the last time.
ATBGE!
Have you looked at OnShape? It’s browser based and cloud based (your models are open to the public if you use it for free) but it’s pretty solid for basic parametric 3d modeling. As well, it comes from an ex-Solidworks founder and feels very familiar but very limited.
I’m a Solidworks Certified Pro and would definitely use it myself, but I’m primarily on Windows so I’m always using Solidworks.