Depends what phone you’re using, how much RAM you have and how many open apps.
Phones with 4GB RAM or less will close apps more often to make space for your current running app.
Chinese phones purposely close background apps to free up RAM which I don’t like. One of the benefits of Android Vs iOS is that Android can do stuff in the background, and this aggressive killing of apps undermines that.
Non Chinese phones with 6GB RAM or more will be less aggressive with closing apps, however it will still close them after a while for battery saving and if you have a lot of apps open it will have to close some to keep your device running fast.
My Sony Xperia 10iii has 6GB RAM and it’s not overly aggressive with closing apps. Overall it’s a really great phone which I highly recommend. It’s Japanese, we all know Sony is an awesome company, and their phonesc are really good.
Plus in some markets the 10iii is still on sale despite the newer 10v having Judy been released. So you can get the 10iii or 10iv at super low prices.