Yup, I definitely think that IF is part of the magic. Ketosis makes IF easier, in my experience, because of that elimination of the hunger impulse. Even on the days I do eat, it's usually not til mid afternoon - I don't intentionally practice IF anymore, but my eating patterns tend to fall naturally into an 16/8 window.
It's very hard to adapt initially, especially if you grew up religiously starting the day with breakfast, but the difference is pretty evident once the adaptation happens!
Before people say I'm weird and never get hungry, not true. Before IF, I used to wake up in the morning because I was hungry. Early in IF it was hard. But, the body adapts. You push through, and now I feel at my best mentally and athletically before my first feeding of the day.
Also like you, while I don't follow a strict keto diet, I cook most of my meals and stay pretty healthy including rice or potato only sometimes. If I go crazy and have a carb heavy meal, I do end up hungry the next day. Understanding one's body is the advantage of getting old I guess :D