Instead of product tours I like how AWS has little info/help buttons that are placed right next to every informational/actionable element on their dashboard. Totally unobtrusive. If you want to understand something on the dashboard that is not obvious at first, you can click on the info/help button that opens a side panel with a lot more information about that particular element (and any associated topics). Most of the time, you just know what you are dealing with (or can guess what that particular topic might mean and you will probably be right).
Incredible that tooltips were killed because braindead """designers""" couldn't figure out how to make them work on mobile.
They'll be reintroduced under a new name in a decade or two with endless self-congratulation. Same as physical car controls.
Here's a solution off the top of my head: have a dedicate "info" button at the OS level. Holding the button disables normal interaction, highlights all inspectable elements, and allows you to click on each one for a description. Like "inspect element" in the browser.