Do you guys know how to fix those issues? My biggest issue is I cannot login to my dedicated server with the termius app since this what I mainly use since this my main ssh client. Thank you really much for your help in advance!
The sudo apt update error and the Software Updater error are the same error. These are caused by an unsigned PPA. The swiftest resolution to this is to remove the broken PPA.
You can open Software & Updates app and in the other tab, scroll down to the graphics-drivers ppa, then click it to select it. Remove it by clicking the remove button.
On Termius, have you added anything to your ~.profile or ~.bashrc files?
Yes, open your file manager to your Home folder (It defaults directly there on opening) and tap the keyboard shortcut ctrl+h
This will show the "hidden" files. Hidden Files are just basic system files rather than your personal docs and downloads... They are noted by having a period in front of the name. I always keep mine revealed.
You will see .bashrc and .profile.
No, these files exist to serve a function.
But you can open them in Text Editor to review their contents. If unsure, you can copy and paste their contents here for others to review.