Technosignatures are pure speculation. There's no reason to believe aliens exist or utilize any particular technology. But if you assume they do, you have some

Technosignatures are pure speculation. There's no reason to believe aliens exist or utilize any particular technology. But if you assume they do, you have some handles you can grab to try and work the problem. I guess the answer to your question is, "why not both?" Look for solar panels, look for fusion reactors, look for whatever you can think of. It's sort of like diversification, the wider your net the less you are speculating. Taken to the extreme where we cover all possible technologies (clearly impossible but bear with me), our speculation becomes "aliens exist and use technology."