As Search Ads Basic runs on a CPI model as opposed to Search Ads Advanced on a CPT model, it will be very hard for you to compete with other ads in each auction.
We have typically seen Search Ads Basic work well only for brand terms only, especially for apps that haven't run Search Ads Advanced previously as the algorithm is unable to build up relevance for other keywords so your ad will only be shown for brand names only.
At Blackbox, we have our own automated Apple Search Ads platform that allows you to set your budget, CPI goal and add keywords you want to appear for. It brings the best of Search Ads Advanced and Search Ads Basic onto one easy to use 24/7 running platform.
You can find out more about Blackbox here: www.blackbox-platform.com
Additionally, we also perform App Store Optimisation (ASO) for your app to improve your metadata. If you'd like to find out more, you can visit our website: www.redboxmobile.com or email: firstname.lastname@example.org
Please let me know if you need any further assistance!