Hive in superseding cycle

I lost a hive over the winter so when my surviving hive built out a swarm cells I split and turned it into a new hive. That hive has been in a cycle of supersedes since the split. Are there factors that prevent the new queen from being properly mated?

She always seems to disappear and then I find the supersedure cells with very little or horrible brood patterns. I have even found mated drones with there guts splayed out in our yard.

Is there anything I can do to help them succeed? Could it just be a line of genetics that are not very good for mating or conditions aren't proper for the queen to successfully mate? The population is still decent and they have 3 deeps ATM.

What might cause the queen to become missing/leaving/killed? External factors like other bugs eating the queen or the hive killing her because she is laying horrible brood patterns?

Would appreciate any advice.

Thanks for reading.