Leaving this here to display my shame.

Why be ashamed? You had an idea that's probably never occurred to the majority of the people on this planet, and you asked for validation. A) that's original thinking and b) that's the first steps in science: I have an idea, is it reasonable, how can I experiment with it? I think this is a fantastic post!

Honestly there is never any shame about sharing what you've learned. I didn't ever think about this and now I've learned something. Keep asking questions and searching for answers!

According to your link, this is actually used in big plants:

Vacuum distillation is often used in large industrial plants as an efficient way to remove salt from ocean water, in order to produce fresh water. This is known as desalination. The ocean water is placed under a vacuum to lower its boiling point and has a heat source applied, allowing the fresh water to boil off and be condensed.

Leaving this hear to display my shame.

This is your real shame.

yes you can do this, however notice: this is wasteful as you have to run pump and heat from steam condensing is not recovered. You can heat up incoming water with condensing steam - this is called vapour recompression distillation. alternatively you can use heat pump to move heat around

You could but the reality is that using a semipermeable membrane and a difference in pressure is more energy efficient.

I could be wrong, but iirc even tho you can boil the water at lower temperature, it still takes the same amount of energy to change phase, so the efficiency gain isnt as spectacular as you might expect.