i'm a musician and audio engineer who encounters iPads for work regularly. my fine motor control is good enough to get paid to mix or play -- not good enough to reliably bring all open apps up (used to be a long press on the one button) so i can swipe one off screen to "close" it. feel for ya.
Try paying attention to the UI hints. When part of the previous app shows up on the left of the screen, that’s when you’ll get the app switcher.
Here’s a decent video showing the principle: https://youtube.com/watch?v=ewhAR7BmoMM Note that he lets go when the UI hint shows up on the left, but no earlier.
