Anyone else feel like coaching is based on too little data?

Our managers spend hours coaching agents, but it's all based on a tiny sample of calls. We probably review 2-3% of everything that comes through, so it feels like we're missing a lot. We've started using Cresta for some of the repetitive interactions, but I'm still trying to figure out the QA side. I don't want AI replacing managers, I just want it to surface the calls that actually need attention. For teams with high call volume, did automated QA actually improve coaching or just create more work?