New phone will shut down unnecessary apps running on background automatically. There are apps that can tell you what apps are running in the background and offer option to you to kill apps.

Many apps running in background nowadays especially social media apps. If you have many friends in various social media apps, then these will take up the memory and reducing available RAM Weather monitoring. Calendar event, etc.... but these are basic and normally run in background.

Huawei is too aggressive killing background apps until VLC banned itself from being installed into Huawei phone