This can be caused by these errors:
This is the Broadcom proprietary hardware and driver and if it stutters, it can create pauses with kernel operation. If this is happening enough, graphics relay can also be delayed.
sudo modprobe -r wl
sudo modprobe brcmsmac
If that *does not work, you can revert with:
sudo modprobe -r brcmsmac
sudo modprobe wl
Can you try
sudo pam-auth-update
And check that Gnome Keyrings is enabled in Settings.
From another thread, you posted your graphics:
VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09) and for what you wrote here, it says: atomic mode settings. card1 (i915)
Hopefully, you are not trying to run that on Wayland.
I would disable Panel Self Refresh on that with the grub parameter i915.enable_psr=0 (Do Not Use nomodeset)
I believe later Mesa releases have regressions that can affect Haswell, so using SNA acceleration is necessary:
In /etc/X11/xorg.conf.d/20-intel.conf
Section "Device"
Identifier "Intel Graphics"
Driver "intel"
Option "AccelMethod" "sna"
EndSection
This is not unusual when multiple audio management programs are in place. I often must point out to Choose One - to not mix Alsa, Pulseaudio and Pipewire all on one system.
They fight like chickens.
This is not your fault. Many distros just include all, hoping for the best, including Ubuntu.
The latest Pipewire is great on new systems but on an older Mac, probably shows its fangs.
Test:
systemctl --user stop pipewire pipewire-pulse
systemctl --user start pulseaudio
GnuLinux is a beast.
But much of what you are experiencing shows the outer limits - a Proprietary Notebook intended for exclusive Apple use; age of the Notebook; in addition to changes and regressions in later kernel releases.
Saving the older machine from the landfill is a good choice. But comes with extra work...