Game freezes for several seconds when Unloading scene

Hello everyone. I’m implementing an additive load scene in my game. The idea is that when reaching the end of one level, the next one gets added on top of it so the player can transition seamlessly into it. Then after a certain point in the new level, the old one gets removed. However, the game is freezing for several seconds when unloading the old scene. To do that I’m using SceneManager.UnloadSceneAsync(sceneName). It seems like it’s not asynchronous at all. Nothing I try seems to be working even a tiny bit. This happens both in the editor and in builds.

Please help.

I’m using Unity 2022.3.26f1.