I do data preparation as part of the preprocessing in Python. All data is available as a relational database and I can transform it arbitrarily.
Self hosting is preferred and cloud is acceptable if the solution complies with GDPR.
I had a look at PowerBI but find it unintuitive to use. Dash and D3.js might work but they're a bit too low level for my skillset. Is there anything that is on a similar level of abstraction as PowerBI but with better UX?