Whilst there is nothing like Revit on the iPad (or indeed the Mac!) have you come across Shapr3D before? Its about as close to AutoCAD/Fusion as I have found on the platform and incredibly intuitive to use. Its good for technical drawings as much as 3D work. Its not a replacement for either of those apps but I find it useful as a backup nonetheless. https://carlst-james.medium.com/the-ipad-apps-i-actually-use-at-work-c07d0cb2abab