Does poor sleep actually affect weight and appetite hormones, or is that overstated?

It's a real, well-documented effect, not overstated. Sleep deprivation has been shown to increase ghrelin (the hunger hormone) and decrease leptin (the fullness hormone), which together tend to increase appetite and cravings, particularly for higher-calorie foods. Poor sleep is also linked to reduced insulin sensitivity over time. It's not the only factor in weight regulation, but it's a legitimate and measurable one, not just wellness-culture talk. References: https://obesitycanada.ca/healthcare-professionals/adult-clinical-practice-guideline/