My XSMax with a very thin Apple leather case slips out from time to time and pushes both sticks back. Not a good feeling, THANK the Lord for OA. Taking my phone out of arguably the thinnest cover available is a major PITA. This controller is very cantankerous.
They work great. I have an android in a case no problem. He makes it so you can cut out part of the insert so you can take something that is thicker. The kicker and device to shut the battery off work well. I ordered a second pair in case.