If using a lower-versioned custom, i.e., reiser4, kernel we do not want to do an apt-get [-t buster-backports || bullseye-backports] dist-upgrade as our custom kernel would be replaced. However, apt-get [-t buster-backports || bullseye-backports] upgrade may not install/upgrade all packages which, for instance, may be needed to view videos online. It can be fixed as:
apt-get [-t buster-backports || bullseye-backports] install libgl1-mesa-dri mesa-va-drivers mesa-vdpau-drivers mesa-vulkan-drivers