Hi lockdown_izzy,
Welcome to the Apple Support Communities. Being able to rely on your iPhone is always important. I see from your post that your iPhone isn't starting up, and you've tried a force restart already.
This resource has the steps you'll need: If your iPhone, iPad, or iPod touch won't turn on or is frozen. Is this the exact process you used when you tried the force restart?
"iPhone 8 or later: Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then press and hold the Side button until you see the Apple logo."
If that didn't work for you, you would need to connect your device to a computer and follow the "If your device turns on but gets stuck during start up" section of the link I posted above.
Have a great rest of your day.