It looks like you are in exactly the same place I was in, about a year ago. That said, after much research I went with a diaphragm pump from Hiblow, the 120LL.

here's a link - https://www.wholesalesepticsupply.com/products/hiblow-hp-120ll-septic-air-pump?variant=17783425412

You could either run power to the pond or an air line, I wouldn't worry about a loss of output as long as the airline run is not too small. I never had an issue with condensation or freeze up, but my line is pitched towards the pond.

I used 3/4" Pex tubing, a 250' roll was about $60 and used it all, plenty of output for two diffusers in my 1 acre pond.

It's been a year now, and it ran constantly through the cold months, now on a timer to turn off in the hot weather. Highly recommend!