Not able to update after adding ppa ; no pubkey

I’m trying to install lutris on Linux Mint.
After adding ppa and updating i get this error:

`sudo add-apt-repository ppa:lutris-team/lutris
  
You are about to add the following PPA:
 Stable releases for the Lutris client
 More info: https://launchpad.net/~lutris-team/+archive/ubuntu/lutris
Press Enter to continue or Ctrl+C to cancel

Executing: /tmp/apt-key-gpghome.Xv9WsjTa7J/gpg.1.sh --keyserver hkps://keyserver.ubuntu.com:443 --recv-keys 82D96E430A1F1C0F0502747E37B90EDD4E3EFAE4
gpg: key 37B90EDD4E3EFAE4: public key "Launchpad PPA for lutris" imported
gpg: Total number processed: 1
gpg:               imported: 1
gpg: invalid key resource URL '/tmp/apt-key-gpghome.Xv9WsjTa7J/home:manuelschneid3r.asc.gpg'
gpg: keyblock resource '(null)': General error
gpg: key 7721F63BD38B4796: 2 signatures not checked due to missing keys
gpg: key 1488EB46E192A257: 1 signature not checked due to a missing key
gpg: key 1488EB46E192A257: 1 signature not checked due to a missing key
gpg: key A6616109451BBBF2: 12 signatures not checked due to missing keys
gpg: key 3B4FE6ACC0B21F32: 3 signatures not checked due to missing keys
gpg: key D94AA3F0EFE21092: 3 signatures not checked due to missing keys
gpg: key C8CAB6595FDFF622: 2 signatures not checked due to missing keys
gpg: key 871920D1991BC93C: 1 signature not checked due to a missing key
gpg: Total number processed: 11
gpg:       skipped new keys: 11
kush@mint:~$ sudo apt update
Ign:1 http://mirrors.evowise.com/linuxmint/packages ulyssa InRelease
Hit:2 http://mirrors.evowise.com/linuxmint/packages ulyssa Release             
Hit:3 http://dl.google.com/linux/chrome/deb stable InRelease                   
Hit:4 http://download.opensuse.org/repositories/home:/manuelschneid3r/xUbuntu_20.04  InRelease
Hit:6 http://repository.spotify.com stable InRelease                           
Hit:7 http://archive.ubuntu.com/ubuntu focal InRelease                         
Hit:8 http://archive.canonical.com/ubuntu focal InRelease                      
Get:9 http://security.ubuntu.com/ubuntu focal-security InRelease [109 kB]
Hit:10 http://archive.ubuntu.com/ubuntu focal-updates InRelease                
Get:11 http://ppa.launchpad.net/lutris-team/lutris/ubuntu focal InRelease [18.1 kB]
Get:12 http://archive.ubuntu.com/ubuntu focal-backports InRelease [101 kB]     
Err:11 http://ppa.launchpad.net/lutris-team/lutris/ubuntu focal InRelease      
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 37B90EDD4E3EFAE4
Reading package lists... Done                                        
W: GPG error: http://ppa.launchpad.net/lutris-team/lutris/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 37B90EDD4E3EFAE4
E: The repository 'http://ppa.launchpad.net/lutris-team/lutris/ubuntu focal InRelease' is not signed.
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.`

Btw i’ve already tried manually getting key, saving and updating using sudo apt-key add but it doesn’t work.
Any workarounds?