This sounds about right. My parents only use their browsers. They literally do not use any applications outside of the browser. They would be just fine on Linux but change is scary and everything just works.

Check out the Dell Wyse 5070. You can find them used within your budget.

Rsync is what you’re after, especially if you’re moving large files. I regularly transfer hundreds of gb using rsync and it’s great.

https://mxroute.com/ or https://www.fastmail.com/

I picked up a cheap lifetime account on mxroute a while back and have been pretty happy with it.