What's the testing/QA approach in startups these days? - I will not promote

I'd love to learn about the testing/QA approach in startups these days considering the agentic coding and everything else. I'm not interested in the traditional approaches and blind test automation answers. I'm already deep into those and seen with multiple startups that they invested a lot in automation without much ROI and lots of maintenance cost/resources(even with AI) and their tests rarely find real critical bugs that internal manual testing or customer usage find. I'm more looking for real challenges