You literally just have to change the setting so it sleeps when you shut the lid. It’s in power options.
Theoretically, yes. In practice, most models have stupidly buggy ACPI implementations in their BIOS.
The struggle is, I’m very sorry to say, real.
https://macpaw.com/how-to/mac-battery-drains-overnight
https://osxdaily.com/2021/10/20/why-macbook-draining-battery-sleeping/
🤷♂️ Seems to be an issue for a lot of people in general 🤷♂️
Edit: gotta love getting down voted for presenting opposing information to people in the Apple cult.