Sounds like you did some other things before MagicMirror

There is a problem w node 24

So do

pm2 stop all 
cd ~/MagicMirror 
rm -rf node_modules
rm package-lock.json
sudo npm install -g n
sudo n 22.22.1
hash -r
node -v

If that produces 22.22.1 ,
then do

npm run install-mm 

And because you selected pm2

installers/mm.sh

MagicMirror should launch now

Please advise results to here

install starting  - Sa Jun  6 00:34:29 CEST 2026
installing on aarch64 processor system
the os is PRETTY_NAME="Debian GNU/Linux 13 (trixie)" NAME="Debian GNU/Linux" VERSION_ID="13" VERSION="13 (trixie)" VERSION_CODENAME=trixie DEBIAN_VERSION_FULL=13.5 ID=debian HOME_URL="https://www.debian.org/" SUPPORT_URL="https://www.debian.org/support" BUG_REPORT_URL="https://bugs.debian.org/"
              gesamt       benutzt     frei      gemns.  Puffer/Cache verfügbar
Speicher:       3789         434        2332          48        1147        3354
Swap:           2047           0        2047
[96mUpdating packages ...[0m
Hit:1 http://deb.debian.org/debian trixie InRelease Hit:2 http://deb.debian.org/debian trixie-updates InRelease Hit:3 http://archive.raspberrypi.com/debian trixie InRelease Hit:4 http://deb.debian.org/debian-security trixie-security InRelease Ign:5 https://download.docker.com/linux/ubuntu trixie InRelease Err:6 https://download.docker.com/linux/ubuntu trixie Release 404 Not Found [IP: 108.138.7.18 443] Reading package lists...
[91mUpdate failed, retrying installation ...[0m
[96mInstalling helper tools ...[0m
Paketlisten werden gelesen…
Abhängigkeitsbaum wird aufgebaut…
Statusinformationen werden eingelesen…
curl ist schon die neueste Version (8.14.1-2+deb13u3).
wget ist schon die neueste Version (1.25.0-2).
git ist schon die neueste Version (1:2.47.3-0+deb13u1).
build-essential ist schon die neueste Version (12.12).
unzip ist schon die neueste Version (6.0-29).
0 aktualisiert, 0 neu installiert, 0 zu entfernen und 0 nicht aktualisiert.
installed node version is v24.16.0
installing on trixie
installed node version = v24.16.0
[0mNo npm engines section specified in package.json, using default=V10.9.4 ...[0m
[96mCheck current Node installation ...[0m
[0mNode currently installed. Checking version number.
[0mMinimum Node version: [1mv22.21.1[0m
[0mInstalled Node version: [1mv24.16.0[0m
[92mNo Node.js upgrade necessary.[0m
[96mCheck current NPM installation ...[0m
[0mNPM currently installed. Checking version number.
[0mMinimum npm version: [1mV10.9.4[0m
[0mInstalled npm version: [1mV11.13.0[0m
[92mNo npm upgrade necessary.[0m
[96mCloning MagicMirror ...[0m
[92mCloning MagicMirror Done![0m
[96mInstalling dependencies ...[0m
> magicmirror@2.36.0 postinstall > git clean -df fonts vendor modules/default > magicmirror@2.36.0 prepare > [ -f node_modules/.bin/husky ] && husky || echo no husky installed. no husky installed. added 381 packages in 1m 85 packages are looking for funding run `npm fund` for details
[92mDependencies installation Done![0m

added 507 packages in 18s

243 packages are looking for funding
  run `npm fund` for details
setting up initial config.js
[96mCheck plymouth installation ...[0m
[96mSplashscreen: Checking themes directory.[0m
[96mSplashscreen: Create theme directory if not exists.[0m
[92mSplashscreen: Changed theme to MagicMirror successfully.[0m
don't know how to disable screen saver on labwc compositor
install and setup pm2
get the pm2 platform specific startup command
startup command = sudo env PATH=$PATH:/home/julian/.nvm/versions/node/v24.16.0/bin /home/julian/.nvm/versions/node/v24.16.0/lib/node_modules/pm2/bin/pm2 startup systemd -u julian --hp /home/julian
[32m[PM2] [39mInit System found: [1msystemd[22m
[1mPlatform[22m systemd
[1mTemplate[22m
[Unit]
Description=PM2 process manager
Documentation=https://pm2.keymetrics.io/
After=network.target

[Service]
Type=forking
User=julian
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity
Environment=PATH=/home/julian/.nvm/versions/node/v24.16.0/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/games:/usr/games:/home/julian/.nvm/versions/node/v24.16.0/bin:/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
Environment=PM2_HOME=/home/julian/.pm2
PIDFile=/home/julian/.pm2/pm2.pid
Restart=on-failure

ExecStart=/home/julian/.nvm/versions/node/v24.16.0/lib/node_modules/pm2/bin/pm2 resurrect
ExecReload=/home/julian/.nvm/versions/node/v24.16.0/lib/node_modules/pm2/bin/pm2 reload all
ExecStop=/home/julian/.nvm/versions/node/v24.16.0/lib/node_modules/pm2/bin/pm2 kill

[Install]
WantedBy=multi-user.target

[1mTarget path[22m
/etc/systemd/system/pm2-julian.service
[1mCommand list[22m
[ 'systemctl enable pm2-julian' ]
[32m[PM2] [39mWriting init configuration in /etc/systemd/system/pm2-julian.service
[32m[PM2] [39mMaking script booting at startup...
[32m[PM2] [39m[-] Executing: [1msystemctl enable pm2-julian[22m...
[32m[PM2] [39m[1m[v] Command successfully executed.[22m
[1m[34m+---------------------------------------+[39m[22m
[1m[34m[32m[PM2] [34mFreeze a process list on reboot via:[39m[22m
[1m$ pm2 save[22m

[1m[34m[32m[PM2] [34mRemove init script via:[39m[22m
[1m$ pm2 unstartup systemd[22m
pm2 startup command done
configure the pm2 config file for MagicMirror
rename pm2 process in pm2_MagicMirror.json
the user is not pi
change pm2_MagicMirror.json
now using this config file pm2_MagicMirror_new.json
start MagicMirror via pm2 now
save MagicMirror pm2 config now
stop MagicMirror via pm2 now
[92mWe're ready! Run [1m[97mpm2 start MM[0m[92m from the ~/MagicMirror directory to start your MagicMirror.[0m

The scripted install is here
https://github.com/sdetweil/MagicMirror_scripts