More than likely this is a torque converter issue. This is pretty common on these units but we need to test this just to confirm it.
Just in case this does not prove out, here is a guide that will help with stalling at idle. Not all of these will apply but we need to run through them just to be sure.
However, please see the info below and let us know what you find. Specifically look at number 6 on this testing.
Images (Click to enlarge)
Thursday, July 22nd, 2021 AT 6:46 PM