The thing I like about Retool is that it's pretty easy to just drop to code within Retool itself, provided you're willing to write JavaScript. You can write JS "queries" that just run a piece of code, and you can create completely custom React UI components. You can also write JS for things like conditional formatting of table rows, generating and exporting a CSV file the user can download, transforming API responses, and so on. And you can still take advantage of Retool's automatic coaching and reloading to some extent. In my last job I built a number of fairly complex dashboards with Retool alongside my normal work, including one with an interactive network graph.