As we depend against qt5.15 we can use qt macro/Qt::

autotests/app/CMakeLists.txt

@@ -4,6 +4,6 @@ ecm_add_test(
     batchextracttest.cpp
     ${CMAKE_SOURCE_DIR}/app/batchextract.cpp
     ${CMAKE_BINARY_DIR}/app/ark_debug.cpp
-    LINK_LIBRARIES Qt5::Test KF5::KIOFileWidgets kerfuffle
+    LINK_LIBRARIES Qt::Test KF5::KIOFileWidgets kerfuffle
     TEST_NAME batchextracttest
     NAME_PREFIX app-)

autotests/kerfuffle/CMakeLists.txt

@@ -18,17 +18,17 @@ ecm_add_tests(
     createdialogtest.cpp
     metadatatest.cpp
     mimetypetest.cpp
-    LINK_LIBRARIES testhelper kerfuffle Qt5::Test KF5::ConfigCore KF5::KIOCore
+    LINK_LIBRARIES testhelper kerfuffle Qt::Test KF5::ConfigCore KF5::KIOCore
     NAME_PREFIX kerfuffle-)
 
 ecm_add_test(
     adddialogtest.cpp
-    LINK_LIBRARIES kerfuffle Qt5::Test KF5::KIOFileWidgets
+    LINK_LIBRARIES kerfuffle Qt::Test KF5::KIOFileWidgets
     NAME_PREFIX kerfuffle-)
 
 ecm_add_tests(
     jobstest.cpp
-    LINK_LIBRARIES jsoninterface Qt5::Test
+    LINK_LIBRARIES jsoninterface Qt::Test
     NAME_PREFIX kerfuffle-)
 
 # metadatatest needs the number of plugins actually installed by an install() command.

autotests/plugins/cli7zplugin/CMakeLists.txt

@@ -9,6 +9,6 @@ ecm_add_test(
     cli7ztest.cpp
     ${CMAKE_SOURCE_DIR}/plugins/cli7zplugin/cliplugin.cpp
     ${CMAKE_BINARY_DIR}/plugins/cli7zplugin/ark_debug.cpp
-    LINK_LIBRARIES testhelper kerfuffle Qt5::Test
+    LINK_LIBRARIES testhelper kerfuffle Qt::Test
     TEST_NAME cli7ztest
     NAME_PREFIX plugins-)

autotests/plugins/clirarplugin/CMakeLists.txt

@@ -9,6 +9,6 @@ ecm_add_test(
     clirartest.cpp
     ${CMAKE_SOURCE_DIR}/plugins/clirarplugin/cliplugin.cpp
     ${CMAKE_BINARY_DIR}/plugins/clirarplugin/ark_debug.cpp
-    LINK_LIBRARIES testhelper kerfuffle Qt5::Test
+    LINK_LIBRARIES testhelper kerfuffle Qt::Test
     TEST_NAME clirartest
     NAME_PREFIX plugins-)

autotests/plugins/cliunarchiverplugin/CMakeLists.txt

@@ -9,7 +9,7 @@ ecm_add_test(
     cliunarchivertest.cpp
     ${CMAKE_SOURCE_DIR}/plugins/cliunarchiverplugin/cliplugin.cpp
     ${CMAKE_BINARY_DIR}/plugins/cliunarchiverplugin/ark_debug.cpp
-    LINK_LIBRARIES testhelper kerfuffle Qt5::Test
+    LINK_LIBRARIES testhelper kerfuffle Qt::Test
     TEST_NAME cliunarchivertest
     NAME_PREFIX plugins-)
 

autotests/plugins/clizipplugin/CMakeLists.txt

@@ -9,6 +9,6 @@ ecm_add_test(
     cliziptest.cpp
     ${CMAKE_SOURCE_DIR}/plugins/clizipplugin/cliplugin.cpp
     ${CMAKE_BINARY_DIR}/plugins/clizipplugin/ark_debug.cpp
-    LINK_LIBRARIES testhelper kerfuffle Qt5::Test
+    LINK_LIBRARIES testhelper kerfuffle Qt::Test
     TEST_NAME cliziptest
     NAME_PREFIX plugins-)

autotests/testhelper/CMakeLists.txt

@@ -5,4 +5,4 @@ set(TESTHELPER_SOURCES
     testhelper.cpp)
 
 add_library(testhelper STATIC ${TESTHELPER_SOURCES})
-target_link_libraries(testhelper Qt5::Test kerfuffle)
+target_link_libraries(testhelper Qt::Test kerfuffle)

kerfuffle/CMakeLists.txt

@@ -62,7 +62,7 @@ PUBLIC
     KF5::I18n
     KF5::WidgetsAddons
 PRIVATE
-    Qt5::Concurrent
+    Qt::Concurrent
     KF5::ConfigCore
     KF5::KIOCore
     KF5::KIOWidgets

part/CMakeLists.txt

@@ -18,7 +18,7 @@ ecm_qt_declare_logging_category(arkpart
                                 IDENTIFIER ARK
                                 CATEGORY_NAME ark.part DESCRIPTION "Ark KPart" EXPORT ARK)
 set(ark_adaptor_SRCS)
-qt5_add_dbus_adaptor(ark_adaptor_SRCS dnddbusinterface.xml part.h Ark::Part)
+qt_add_dbus_adaptor(ark_adaptor_SRCS dnddbusinterface.xml part.h Ark::Part)
 target_sources(arkpart PRIVATE ${ark_adaptor_SRCS})
 ki18n_wrap_ui(arkpart
     arkviewer.ui