Interesting. I am a developer for about +30 years from the classic mas OS 9 up to the latest macOS26 and I my experience macOS26 has very little issues with memory leaks. In fact, the last couple macOS versions are insanely good in detecting unreleased memory addresses. Even for badly writing apps, it covers those leaks not directly related to macOS itself. It's even hard to code an app with Swift that does leak memory.
So, unless you just shouting, it would be awesome if you can share some recordings with Instruments/Leaks profiles so we can take a look at it.