Hi @fixit7,
The following PPA's do not support Ubuntu 24.04 LTS and are (part of) the reason that you get those update-manager errors, you really want to remove them.
UNetbootin -> gezakovacs-ubuntu-ppa-noble.sources
Ubuntu Tweak -> tualatrix-ubuntu-ppa-noble.sources
By the way, you also don't need pj-assis-ubuntu-ppa-noble.sources
because guvcview is nowadays in the standard repositories, so this is another one that can be removed.
Info about how to remove a PPA:
Ubuntu Tweak is dead, see this link:
software installation - How do I install Ubuntu-Tweak? - Ask Ubuntu
UNetbootin can only be downloaded from their site.
Use this link if needed and download the 64-bit version.
UNetbootin - Linux Downloads
then open the directory where you downloaded this and make the downloaded file executable. It should be a file named like this: unetbootin-linux64-702.bin
Run it from a terminal with:
QT_X11_NO_MITSHM=1 ./unetbootin-linux64-702.bin "rootcheck=no"
or create a .desktop file for it