The snack and activity prep before your workday starts makes a huge difference. Set up a snack station the night before or early morning with stuff they can grab themselves - crackers, fruit, yogurt, whatever doesn't need your hands. Same with activities: have a rotation of things that actually hold their attention for chunks of time. For my kids at similar ages, it was a mix of building sets, coloring with new markers (novelty helps), educational apps, and outdoor time if the weather's decent. You're not being neglectful by buying them an hour of focused play time instead of constant interaction.
For calls specifically, be upfront with your team about it. Most people get it now and won't mind background noise from kids occasionally. Schedule your most important calls during their quietest time if possible - that's usually right after they eat or during an established quiet hour. Noise-canceling headphones help too, and you can mute yourself during listening parts. The other thing that worked for us was setting a visual boundary they understand, like a specific door being closed means "don't interrupt unless it's an emergency," and keeping emergencies actually defined (blood, fire, actual pain - not boredom).
The hardest part is accepting it won't be perfect. Some days will be chaos and you'll have to reschedule things, and that's just the reality of this setup. But having clear structures - predictable snack times, activities prepped, and realistic expectations from your employer - cuts down the constant reactive firefighting. You'll find your rhythm.