Google Play explore visibility is very black boxy (like UAC) and is pretty tough to gain visibility or an understanding of the influences of.
Google has also been experimenting a LOT on visibility here, and you are not alone in seeing larger Explore numbers. Explore also looks like UAC placements, so Google is likely pushing Explore to increase the likelihood that users will go to recommended lists to download, and ultimately download from UAC placements more often.
It's important to note that Explore is made of 3 sub-components:
- Top charts
- Recommended apps
So any of the above can also influence your Explore, but you can't segment them out. Tracking top chart rank and features helps, but ASO tools have encountered challenges in tracking recommended app lists accurately due to Google's increasing use of personalization to determine recommended placements and rankings.
In terms of how to optimize Explore, you can start by using the tags feature which Google's recent post introducing tags as a lever.
Other influences on Explore can include:
- Ratings volume vs peers
- Star rating vs peers
- Crashes/ANRs/uninstalls etc. vitals vs bad behavior thresholds
- Retention rate vs benchmarks
- Conversion rate vs benchmarks (though this can't be teased out for explore vs search)
Note that these are all concerned with comparison numbers. Google wants to maximize user experience, and rankings are a zero-sum game so you are constantly being compared to competitors/categories to determine which high visibility rankings are deserved.
Organic uplift (inorganic downloads) also has a significant influence on Explore (naturally most correlated with top charts, but likely recommended lists as well). We have seen conversion rate as a very strong factor. Uninstalls and ratings volume/star count have also been found to be influential. Retention rate and vital are likely increasing given Google's explicitly stated focus on those metrics (though it may take time for the algorithms to learn how to care about these metrics in material ways beyond the current top influences).
Offline datasets (whose user devices your app is installed on) are a huge factor in recommendation lists, but this is hard to influence/game, which is likely Google's goal in pushing Explore traffic, to preclude marketers' constant efforts to infuence their algorithms.
Here are some slides discussing influences on Google's algorithm, and another post discussing how ASO is evolving, with mentions on how Google is pushing more explore visibility.