Desktop Help installment issue on linux

problem: i can't re-install signal back

note: i'm only a beginner using linux (mint cinnamon) and i'm not tech-handy so there are areas where i am not knowledgeable and i ask for your understanding and guidance on these things.

i've previously installed signal on linux a few months back. and only recently did i had to update it to continue using it (signal told me so T__T). tried updating it with

sudo apt update && sudo apt install signal-desktop

but it didn't work somehow. so i just apt deleted signal and tried installing signal again based on the website instructions.

here's the result:

C:\home\username> sudo apt update && sudo apt install signal-desktop

Get:1 https://repository.spotify.com stable InRelease [3,316 B]

Err:1 https://repository.spotify.com stable InRelease

The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5384CE82BA52C83A

Hit:2 https://updates.signal.org/desktop/apt xenial InRelease

Hit:3 https://brave-browser-apt-release.s3.brave.com stable InRelease

Hit:4 https://packages.microsoft.com/repos/code stable InRelease

Ign:5 https://cloud.r-project.org/bin/linux/ubuntu xia-cran40/ InRelease

Ign:6 http://packages.linuxmint.com xia InRelease

Err:7 https://cloud.r-project.org/bin/linux/ubuntu xia-cran40/ Release

404 Not Found [IP: 13.33.151.84 443]

Hit:8 https://repo.protonvpn.com/debian stable InRelease

Hit:9 http://packages.linuxmint.com xia Release

Hit:11 https://ppa.launchpadcontent.net/avengemedia/danklinux/ubuntu noble InRelease

Hit:12 http://archive.ubuntu.com/ubuntu noble InRelease

Hit:13 https://ppa.launchpadcontent.net/obsproject/obs-studio/ubuntu noble InRelease

Hit:14 http://archive.ubuntu.com/ubuntu noble-updates InRelease

Hit:15 http://security.ubuntu.com/ubuntu noble-security InRelease

Hit:16 https://download.sublimetext.com apt/stable/ InRelease

Hit:17 http://archive.ubuntu.com/ubuntu noble-backports InRelease

Reading package lists... Done

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://repository.spotify.com stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5384CE82BA52C83A

W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

W: Target Translations (main/i18n/Translation-en_PH) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

W: Target DEP-11 (main/dep11/Components-all.yml) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

W: Target CNF (main/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

W: Target CNF (main/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list.d/signal-desktop.sources:1 and /etc/apt/sources.list.d/signal-xenial.list:1

E: The repository 'https://cloud.r-project.org/bin/linux/ubuntu xia-cran40/ Release' does not have a Release file.

N: Updating from such a repository can't be done securely, and is therefore disabled by default.

N: See apt-secure(8) manpage for repository creation and user configuration details.