On Linux/Wayland the latest Qt online installer and the Qt Maintenance Tool don't install qt6-wayland.

Because of that, Qt Creator 6.0.1 (build using Qt 6.2.2) doesn't run in native Wayland mode and got blurry fonts on HiDPI graphics. If QT_QPA_PLATFORM=wayland is defined, the Qt Online-Installer Open Source, Qt Creator 6.0.1 and Qt Maintenance Tool won't even start.

Manual workaround on Arch Linux to enable Qt Creator 6.0.1 native Wayland mode:

Define QT_QPA_PLATFORM=wayland in /etc/environment

Install qt6-wayland package

Copy directories: (be sure to copy the same Qt version Qt Creator was build with - for example Qt Creator 7.0 beta 1 needs Qt 6.2.3):
.../Qt/6.2.2/gcc_64/plugins/platforms
.../Qt/6.2.2/gcc_64/plugins/wayland-decoration-client
.../Qt/6.2.2/gcc_64/plugins/wayland-graphics-integration-client
.../Qt/6.2.2/gcc_64/plugins/wayland-graphics-integration-server
.../Qt/6.2.2/gcc_64/plugins/wayland-shell-integration
to (overriding existing folders)
.../Qt/Tools/QtCreator/lib/Qt/plugins/platforms
.../Qt/Tools/QtCreator/lib/Qt/plugins/wayland-decoration-client
.../Qt/Tools/QtCreator/lib/Qt/plugins/wayland-graphics-integration-client
.../Qt/Tools/QtCreator/lib/Qt/plugins/wayland-graphics-integration-server
.../Qt/Tools/QtCreator/lib/Qt/plugins/wayland-shell-integration

Haven't found a workaround for Qt Maintenance Tool to run in native Wayland mode yet.

Edit 16. February 2022:
QT_QPA_PLATFORM=wayland environment variable isn't necessary anymore to force Qt Creator to run under Wayland since Qt Creator 7.0 beta 1