I'm going to suggest you just give up manually manipulating your phone's recently open apps. Unless an individual app is having a problem, by trying to micromanage your phone's memory management you're not really helping it run better, you're instead forcing it to work that much harder than it needs to.
Android memory management is a lot more sophisticated than we think we are. Opened apps get retained in the RAM as an intended function, and the memory management will kill off those running background processes but only when necessary. With Android, having high numbers of RAM usage is a sign your phone is working as it should be.
A lot of people mistakenly assume Android is using the same antiquated memory management as Windows XP so they instinctively think manually killing off running processes is helping. What you're doing is creating a situation where apps you use frequently could be launching faster but cannot, because you're intentionally interfering with the basic functionality.