ew!

They want us to get a booster shot after 8 months. So you are protected for at least 8 months. Was it worth it? Well, 1.6% of the people that got Covid-19 in the USA died from it. A larger percentage have "long hauler" symptoms that may never go away. Who knows what other weird issues may show up. It's a virus, sometimes problems show up years later.

Hardware stores sell multimeters now. Big box home center stores too.

I've seen a program called Synergy that probably does what you want. I believe LAPD was using it when I heard about it. You roll the mouse pointer off the edge of one screen and it appears on the other monitor. The keyboard control follows the mouse.