Some recent tablet pens support haptic feedback, such as the Microsoft Surface Pen. There appears to be roughly two feature levels, first is basic feedback like buzzing to signal events like clicks or errors. More interestingly, newer pens support complex waveforms that make the pen feel like it is on a textured surface like canvas or paper.

This textured feel is one of those features one really wants once it's experienced. Videos and text reviews do not do it justice.

Would it be possible to add support for this to Qt so art programs like Krita could take advantage?

Microsoft's documentation makes it seem fairly straight forward: https://learn.microsoft.com/en-us/windows/apps/design/input/pen-haptics#send-and-stop-inking-haptic-feedback