Google home app (the ONLY way you can control the Google Nest Thermostat), offers 3 "ready-made" presets: Comfort, Eco and Sleep. You cannot delete any of those 3 presets, however you can delete your own that you create.
When you interact with the Nest using a native Nest app, I'm sure there are more options and ways to control these presets. Unfortunately this Nest: https://www.amazon.com/Google-Nest-Thermostat-Smart-Programmable/dp/B08HRWWCTR/ref=sr_1_6?keywords=nest+thermostat&qid=1688309556&sprefix=nest+the%2Caps%2C141&sr=8-6simply links directly to google home and you cannot control presets through either the thermostat itself or through an independent Nest app. Google home has you by the balls:(