The most likely culprit here is a load-switching issue, specifically how smart bulbs handle constant power versus the momentary surge from a high-wattage appliance or switch on the same circuit. Since the kitchen lights are likely on a different circuit than your hallway, the flickering you see is probably not a wiring problem, but rather a power dip affecting the smart bulbs as the main circuit resets its voltage draw. Most smart bulbs, even when they appear 'off,' are actualy constantly drawing a small amount of power to maintain thier connection and wait for commands. When the kitchen light switch engages a heavy load, it causes a momentary voltage drop throughout the entire home. This dip isn't always enugh to trip a breaker, but it is definately enough to cause a reactive dimming pulse in the sensitive internal circuitry of those smart bulbs.
Before you start swapping every bulb for a different brand, which can be a waste of money if the wiring is fine, check your breaker panel first. If the kitchen and hallway are on different breakers, then the problem is definitely the current draw on the kitchen side. If they are on the same breaker, then you have a serious load imbalance issue that needs a professional to address. If you confirm they are on seperate circuits, the smart bulbs themselves might just be sensitive to minor fluctuations. Some brands are much better at handling 'dirty power' than others. If you want to test this theory, try replacing one of the bulbs with a basic non-smart incandescent bulb. If the flickering stops, you know it is purely a smart bulb compatibility issue with your local voltage stability. Older homes often have wiring that was perfectly fine in the 70s but struggles with the cumulative electronic demands of modern smart devices. Testing that load distribution is the best first step.