Pegasus is spyware that was designed for installation on mobile phones running iOS or Android, so obviously it can't have been installed on 'all of your devices' if you're posting this from a Windows device.
These are always scams and everyone helping here knows this, but the scammers know that most people are fools when it comes to computers, so they take advantage of that fact to scam them for ridiculous amounts of money for nothing.
It wasn't sent from your email, it was Spoofed, or faked to appear as if your email sent it in order to help trick you into believing the scammer has access to your device. They don't, any knowledgeable kid today can change an email 'From' address field to display anything they wish, since that's always been a 'feature' of the SMTP email RFC called a 'display name' or 'friendly name' to allow something 'nicer' than an email address to appear there.
All of these things are commonly known and have been discussed on these and many other forums literally thousands of times, but nobody tries to find them until they're actually scammed, which the scammer tries to get you not to do in a panic in order to pay them for not knowing these simple facts.
If your version of the hundreds of variants included passwords, then change those immediately to something much different.
If not, it's simply another scam, so either move the email message to your Junk or Spam email folder to tell your email provider that, if it wasn't already placed in that folder automatically as all of the one's I've received have been.
Otherwise, just delete the fake message and get on with life, you've wasted too much time on it already.
Rob