Boost Apple Ads Conversions

My Apple Search Ads campaigns are running, but the conversion rate to app downloads is well below the benchmarks I’m aiming for. I’ve never set up any A/B tests, so every keyword, creative set, and bid adjustment has been running unchanged for months... (Budget: $250 - $750 USD, Jobs: A/B Testing, App Store Optimization, Conversion Rate Optimization, Digital Marketing, Google Adwords, Internet Marketing, Search Engine Marketing, SEO)