Feedback on the Dell Precision 7560 (202103-28864)

I understand that you're facing several issues with your Dell Precision 7560 running Ubuntu 18.04 LTS, including problems with WiFi, the speaker, audio jack, and screen brightness. Let's address each of these concerns:

WiFi Issue:

Ensure that the necessary wireless drivers are installed. You can check this by opening the Terminal and running the following command:
perl
lspci -k | grep -A3 Network
Identify your wireless card model and search for the appropriate drivers or firmware updates.
Speaker and Audio Jack Not Working:

Verify that the audio drivers are correctly configured. Check the sound settings to ensure the correct output device is selected.
Run the following command in the Terminal to check for audio devices:

aplay -l
If necessary, update or reinstall audio drivers.
Screen Brightness Issue:

Adjusting screen brightness issues may be related to missing or incorrect graphics drivers. Update your graphics drivers to the latest version.
You can use the following command to control screen brightness manually:
css

xrandr --output [your_display] --brightness [value]
Replace "[your_display]" with your actual display name (e.g., "eDP-1"), and "[value]" with a brightness value between 0 and 1.
After attempting these solutions, please provide additional details or error messages if the issues persist. If you have not already, consider upgrading to a newer Ubuntu version, as newer releases often come with improved hardware compatibility and updated drivers.