My ~/Library/Developer/CoreSimulator/Devices
folder is 26 Gb
in size.
Is it safe to just delete all the content? Will those files be automatica
That directory is part of your user data and you can delete any user data without affecting Xcode seriously. You can delete the whole CoreSimulator/ directory. Xcode will recreate fresh instances there for you when you do your next simulator run. If you can afford losing any previous simulator data of your apps this is the easy way to get space.
Update: A related useful app is "DevCleaner for Xcode" https://apps.apple.com/app/devcleaner-for-xcode/id1388020431