Hi everyone! What are your experiences of running Advantage+ campaigns on Meta these days?

Hi everyone! I'm new here so I hope I'm doing this correctly! I have a targeting question. Mostly, my ads sets are running to very broad audiences (women in UK, with little additional definition) because that's what's we've seen working to date. We see reasonably good returns through Meta ads, and they're converting both existing and new customers, which is good. However, I want to flip the existing:new customer weighting to reach more new customers, particularly for certain products. What's the best way to go about this in terms of how I set up new ad sets and ads? Thanks in advance for anyone who can help :)