Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server

Provides :
application()
application(qt5-designer.desktop)
mimehandler(application/x-designer)
qt5-designer
qt5-designer(x86-64)

Requires :

libGL.so.1()(64bit)
libQt5Core.so.5()(64bit)
libQt5Core.so.5(Qt_5)(64bit)
libQt5Core.so.5(Qt_5.15)(64bit)
libQt5Designer.so.5()(64bit)
libQt5Designer.so.5(Qt_5)(64bit)
libQt5DesignerComponents.so.5()(64bit)
libQt5DesignerComponents.so.5(Qt_5.15.3_PRIVATE_API)(64bit)
libQt5Gui.so.5()(64bit)
libQt5Gui.so.5(Qt_5)(64bit)
libQt5Network.so.5()(64bit)
libQt5Network.so.5(Qt_5)(64bit)
libQt5PrintSupport.so.5()(64bit)
libQt5PrintSupport.so.5(Qt_5)(64bit)
libQt5Widgets.so.5()(64bit)
libQt5Widgets.so.5(Qt_5)(64bit)
libQt5Xml.so.5()(64bit)
libQt5Xml.so.5(Qt_5)(64bit)
libc.so.6()(64bit)
libc.so.6(GLIBC_2.14)(64bit)
libc.so.6(GLIBC_2.2.5)(64bit)
libc.so.6(GLIBC_2.3.4)(64bit)
libc.so.6(GLIBC_2.4)(64bit)
libgcc_s.so.1()(64bit)
libm.so.6()(64bit)
libpthread.so.0()(64bit)
libstdc++.so.6()(64bit)
libstdc++.so.6(CXXABI_1.3)(64bit)
libstdc++.so.6(CXXABI_1.3.9)(64bit)
libstdc++.so.6(GLIBCXX_3.4)(64bit)
qt5-qttools-libs-designer(x86-64) = 5.15.3-4.el8
qt5-qttools-libs-designercomponents(x86-64) = 5.15.3-4.el8
rpmlib(CompressedFileNames) <= 3.0.4-1
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(PartialHardlinkSets) <= 4.0.4-1
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
rpmlib(PayloadIsXz) <= 5.2-1
rtld(GNU_HASH)

Content of RPM :
/usr/bin/designer-qt5
/usr/lib/.build-id
/usr/lib/.build-id/eb
/usr/lib/.build-id/eb/3d7dce09568c766002ffe7dc39c153144a4675
/usr/lib/.build-id/eb/3d7dce09568c766002ffe7dc39c153144a4675.1
/usr/lib64/qt5/bin/designer
/usr/lib64/qt5/bin/designer-qt5
/usr/share/applications/qt5-designer.desktop
/usr/share/icons/hicolor/128x128/apps/designer-qt5.png