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To be honest, I had assumed that the Pixel Tablet had haptic feedback too. I would be interested if another Tablet user could confirm whether they have it too.
Is there any chance that it is disabled on your device or for your keyboard app?
Under Settings > Sound & vibration > Vibration and feedback, check that you have 'Use vibration and haptics' toggled on, and that you have the 'touch feedback' slider set higher than the minimum level
Which keyboard app are you using? If you using are GBoard it is possible to disable/enable haptic feedback there separate from the system settings. You can find the haptic feedback setting in GBoard Settings > Preferences > Key press.
Likewise, if you're using the GrapheneOS default Keyboard, it is also possible to enable/disable haptic feedback under global Settings > System > Keyboard > On screen keyboard > (GrapheneOS) Keyboard > Advanced.
Hope that helps!