The 2022 model. By real sleep mode, I mean suspend-to-RAM, or S3. A few years ago, Microsoft declared that they will no longer support sleep mode, and will just call S0 mode "Modern standby" so they can keep doing telemetry nonsense 24/7 when people think their laptop is asleep. Dell saw this and decided that they don't need to support S3 mode in the BIOS any more because they don't want to put in the effort just for Linux users.
https://martinpoehlmann.com/posts/tech/2021-07-30-dell-s3-mo...
https://libreddit.privacydev.net/r/Dell/comments/h0r56s/gett...