Qt-6 toolchain issue with setup yocto - dunfell - Ubuntu

With mention steps/procedure tried building qt6 toolchain in Ubuntu-20.04.6,
but somehow its failing which pointing to spirv-tools, so not sure either its due to broken configuration or some issue in procedure I fallowed. Any thoughts on this would be really helpful.. 

Procedure fallowed:

1.  git clone -b dunfell http://git.yoctoproject.org/git/poky
2.  cd poky
3.  git clone -b dunfell https://git.openembedded.org/meta-openembedded
4.  git clone -b 6.6.2 git://code.qt.io/yocto/meta-qt6.git
5.  source oe-init-build-env
6.  Updated conf/bblayers.conf with adding required layers:
    meta-qt6 meta-openembedded
7. Start toolchain: bitbake meta-toolchain-qt6

Also, may I know documentation link regarding Qt toolchain?

Let me know if any further details required on same.