I once had an interesting experience migrating users from a TUI to a GUI app, ~20 years ago. In that case, after watching them work for a while and asking some questions, the takeaway was that they really wanted the flow to be 100% keyboard-based. Which the GUI apps nominally provided (back then; less so these days), but all too often the correct tab order etc is ignored in practice, making it very difficult to use.
I made sure design the GUI with keyboard in mind, and that common patterns they've learned from TUI would still work. For example, the TUI had a textbox above a listbox, and it was common for users to press arrow-down to navigate from the textbox to the first item in the list, and arrow-up to navigate from the list back into the textbox. This isn't normal behavior for GUI, but I coded it in anyway.