Dash is really the go-to library if you want to build some complex, flexible dashboards. I found for highly customized dashboards it's a lot easier just to program your own instead of squeezing Tableau's rules.
The Devs recently added support for templates which can handle dynamic layouts (i.e drag and drop). https://panel.holoviz.org/reference/templates/React.html#tem...
Here's an example that uses almost entirely higher level components: https://dash-bootstrap-components.opensource.faculty.ai/exam...
We've also been working on `dash.templates`, which provide opinionated, prebuilt UIs - no layout code required: https://community.plotly.com/t/introducing-dash-labs-dash-2-...
It’s also way simpler to just pull everything in and manipulate it in Pandas, if your data is not pristine from the get-go.
That said, Tableau is still useful for the "ordinary" dashboards, e.g. it's a lot easier if you just need to do some simple calculations and get your KPI. Tableau is still way faster than any other programming language.