sudo apt install -y build-essential libglib2.0 libjpeg9 libopenjp2-7 librsvg2-dev imagemagick libtiff5-dev
wget https://github.com/libvips/libvips/releases/download/v8.12.1/vips-8.12.1.tar.gz
tar xfvz vips-8.12.1.tar.gz
cd vips-8.12.1
./configure
make
sudo make install
sudo ldconfig

npm install

It will take a while to compile the library and a lot of disk space will be used.

https://sharp.pixelplumbing.com/install

looks like prebuilt binaries are not produced for 32bit os systems (raspi os)

here is similar sharp problem
https://github.com/lovell/sharp/issues/2287

I don’t know what to do about this

node -v
and npm -v

node -v
v14.18.2
pi@raspberrypi:~/MagicMirror/config $ npm -v
6.14.15

can u also do

node -v
and npm -v

 uname -a
Linux raspberrypi 5.10.63-v7l+ #1488 SMP Thu Nov 18 16:15:28 GMT 2021 armv7l GNU/Linux
pi@raspberrypi:~/MagicMirror/config $ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 11 (bullseye)
Release:        11
Codename:       bullseye

[31mSyntaxError: Unexpected identifier[39m
[31m    at wrapSafe (internal/modules/cjs/loader.js:986:16)[39m
[31m    at Module._compile (internal/modules/cjs/loader.js:1034:27)[39m
[31m    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1108:10)[39m
[31m    at Module.load (internal/modules/cjs/loader.js:935:32)[39m
[31m    at Module._load (internal/modules/cjs/loader.js:776:14)[39m
[31m    at Function.f._load (electron/js2c/asar_bundle.js:5:12913)[39m
[31m    at Module.require (internal/modules/cjs/loader.js:959:19)[39m
[31m    at require (internal/modules/cjs/helpers.js:88:18)[39m
[31m    at loadConfig (/home/pi/MagicMirror/js/app.js:69:14)[39m
[31m    at App.start (/home/pi/MagicMirror/js/app.js:212:3)[39m
/home/pi/MagicMirror/node_modules/electron/dist/electron exited with signal SIGINT
/home/pi/MagicMirror/node_modules/electron/dist/electron exited with signal SIGINT
/home/pi/MagicMirror/node_modules/electron/dist/electron exited with signal SIGINT
[13.12.2021 21:11.52.510] [ERROR] [31mWARNING! Could not load config file. Starting with default configuration. Error found: Error: 'linux-armv7' binaries cannot be used on the 'linux-armvdefault' platform. Please remove the 'node_modules/sharp' directory and run 'npm install' on the 'linux-armvdefault' platform.[39m
[13.12.2021 21:11.52.533] [ERROR] App threw an error during load
[13.12.2021 21:11.52.535] [ERROR] Error: 'linux-armv7' binaries cannot be used on the 'linux-armvdefault' platform. Please remove the 'node_modules/sharp' directory and run 'npm install' on the 'linux-armvdefault' platform.
    at Object.hasVendoredLibvips (/home/pi/MagicMirror/modules/MMM-BackgroundSlideshow/node_modules/sharp/lib/libvips.js:82:13)
    at Object.<anonymous> (/home/pi/MagicMirror/modules/MMM-BackgroundSlideshow/node_modules/sharp/lib/constructor.js:7:22)
    at Module._compile (internal/modules/cjs/loader.js:1078:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1108:10)
    at Module.load (internal/modules/cjs/loader.js:935:32)
    at Module._load (internal/modules/cjs/loader.js:776:14)
    at Function.f._load (electron/js2c/asar_bundle.js:5:12913)
    at Module.require (internal/modules/cjs/loader.js:959:19)
    at require (internal/modules/cjs/helpers.js:88:18)
    at Object.<anonymous> (/home/pi/MagicMirror/modules/MMM-BackgroundSlideshow/node_modules/sharp/lib/index.js:3:15)
[13.12.2021 21:11.52.536] [ERROR] Whoops! There was an uncaught exception...
[13.12.2021 21:11.52.539] [ERROR] Error: 'linux-armv7' binaries cannot be used on the 'linux-armvdefault' platform. Please remove the 'node_modules/sharp' directory and run 'npm install' on the 'linux-armvdefault' platform.
    at Object.hasVendoredLibvips (/home/pi/MagicMirror/modules/MMM-BackgroundSlideshow/node_modules/sharp/lib/libvips.js:82:13)
    at Object.<anonymous> (/home/pi/MagicMirror/modules/MMM-BackgroundSlideshow/node_modules/sharp/lib/constructor.js:7:22)
    at Module._compile (internal/modules/cjs/loader.js:1078:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1108:10)
    at Module.load (internal/modules/cjs/loader.js:935:32)
    at Module._load (internal/modules/cjs/loader.js:776:14)
    at Function.f._load (electron/js2c/asar_bundle.js:5:12913)
    at Module.require (internal/modules/cjs/loader.js:959:19)
    at require (internal/modules/cjs/helpers.js:88:18)
    at Object.<anonymous> (/home/pi/MagicMirror/modules/MMM-BackgroundSlideshow/node_modules/sharp/lib/index.js:3:15)
[13.12.2021 21:11.52.540] [ERROR] MagicMirror will not quit, but it might be a good idea to check why this happened. Maybe no internet connection?
[13.12.2021 21:11.52.540] [ERROR] If you think this really is an issue, please open an issue on GitHub: https://github.com/MichMich/MagicMirror/issues

output of
uname -a
and
lsb_release -a