The output power isn’t meaningless, but it has much less of an effect than the antenna height and gain. A 20 watt radio can easily transmit 100 miles if there are no obstructions, but obstructions are common. A fifty watt radio cannot overcome obstructions, but it can power its way through vegetation which might attenuate the signal of a less powerful radio until it cannot be detected. There are lots of threads which discuss which antennas work well and how and where to mount them. And attenuation affects signals in both directions.
So, more important than the output power is the cable, the antenna gain, the antenna mounting position, and the antenna height. Personally I use a db20g radio with a Midland MXTA26 antenna on the center of my steel roof using a magnetic mount from Midland.