Typical galaxies the size of the Milky Way have 100 to 2,000 billion stars and could have as many as ten trillion planets.

That’s about 100^5, so one way to think of this is that if you categories these by any four properties (temperature, stability, hydration, day length) then you’d expect about 100 samples for any point in that 4D space.

So even if you believe Earth is unique along four critical metrics, there are about a hundred planets per galaxy that also have those attributes within a percentage point. If you allow some wiggle room then you have tens of thousands or even millions.

We know conditions here on Earth varied significantly more than 1% over billions of years and life survived and even thrived.