We changed all input to the new input system on our project.
But the TMP_InputField and other editor scripts still use the UnityEngine.Input class.
It does not make sense to have to use both input systems because of the TextMeshPro.
I hope you don’t answer that you’ll start working after the new input system goes out of preview.
As per my reply to your post in this thread , I do not have an ETA on this yet. Until the New Input System is out of preview, I don’t think it would be prudent to make the switch. Having said that, I can explore adding support for the New Input System in a preview package for 2020.x.