Waste of time yes in the sense that just doing deep tech means it is still basically just an idea. You recognize this. Not a waste of time though if you forese

Waste of time yes in the sense that just doing deep tech means it is still basically just an idea. You recognize this. Not a waste of time though if you foresee your current role ending in a few years and then you have to find something else. It is more common for these side research projects to be helpful in finding a new role. And having gone deep in a domain can make you valuable in consulting.