It can be difficult for developers to take full advantage of the UTxO model because they have to take parallelization into account. Cardano does not allow maintaining a single global application state in the on-chain part of the smart contract. Each UTxO can represent a piece of the application’s state and can be processed independently and in parallel. This theoretically allows for high throughput and scalability, but the application must deal with complexities related to managing concurrent transactions. What challenges do developers face on Cardano?
Read the article: https://cexplorer.io/article/challenges-for-cardano-developers