Where can I find realistic Data Engineering projects?

I'm looking for some real-world Data Engineering projects to work on and add to my portfolio.

I'm not a beginner, so I'm looking for projects beyond basic ETL tutorials — ideally involving things like data pipelines, cloud platforms, data warehouses, Spark, Airflow, orchestration, monitoring, etc.

I've come across ProjectPro and I'm considering their subscription, but I'd like to know from people who have actually used it: are the projects realistic and challenging enough for someone with existing DE experience?

Also, are there any other free/ paid platforms you'd recommend for high-quality Data Engineering projects?

I'd appreciate recommendations based on your actual experience. Thanks!