The Qt Creator Manual contains instructions for configuring builds using .pro files. For each of those, check whether it can be done with CMake, and how. Add notes where only qmake is supported.

• Searching with the Locator: https://doc-snapshots.qt.io/qtcreator-6.0/creator-editor-locator.html
  Creating Projects: https://doc-snapshots.qt.io/qtcreator-6.0/creator-project-creating.html#displaying-additional-file-types-in-projects-view 
  What are the equivalents of DISTFILES and SUBDIRS in CMake?
• Using External Tools: https://doc-snapshots.qt.io/qtcreator-6.0/creator-editor-locator.html
  Using lupdate and lrelease with CMake
• FAQ: https://doc-snapshots.qt.io/qtcreator-6.0/creator-faq.html#qml-and-qt-quick-questions
  What is the equivalent of QML_IMPORT_PATH in CMake?
  What is the equivalent of CONFIG += console in CMake?
• Deploying Applications to Generic Remote Linux Devices: https://doc-snapshots.qt.io/qtcreator-6.0/creator-deployment-embedded-linux.html
  INSTALLS variable? (The process with CMake is actually already described, and its validity for Qt Creator 6.0 and Qt 6 should be checked.)
• Starting QML Debugging: https://doc.qt.io/qtcreator/creator-debugging-qml.html#starting-qml-debugging
  CONFIG +=qml_debug
• Adding Libraries to Projects: https://doc.qt.io/qtcreator/creator-project-qmake-libraries.html
  Example code with CONFIG, LIBS, PRE_TARGETDEPS
• Beautifying Source Code: https://doc-snapshots.qt.io/qtcreator-master/creator-beautifier.html 
  DISTFILES
• Specifying Supported iOS Versions: https://doc-snapshots.qt.io/qtcreator-master/creator-developing-ios.html#specifying-supported-ios-versions 
  QMAKE_IOS_DEPLOYMENT_TARGET
• Integrating Wizards into Builds: https://doc-snapshots.qt.io/qtcreator-master/creator-project-wizards.html#integrating-wizards-into-builds
  Build > Run CMake?