It has a supposedly intelligent thing which works about the same as iOS, meaning not well and not reliably.

iOS has gained a hard limit toggle, but macOS has yet to. Aldente does that job.

The built-in option is a step in the right direction, but doesn't provide any way for a user to specify that the battery doesn't need to be charged to 100% if the OS thinks it needs to be. In my experience, it usually ends up charging the battery 100% every night, then letting it discharge to 80% during the day.

I’ve had it never charge, and sit reliably at 80% for weeks. Then when I unplugged it the schedule was ruined and it reverted to charging at night. Overcomplicated for no reason lol

Yes: the MacBook eventually learns to stop charging and keep at 80%. (it took a month for mine)

You can override it to fully charge.