Samsung Galaxy A71 works pretty good. I have a thin silicone case and I get good reads with it on, but better with it off of course. Antenna is located next to the camera block, but I find the best reads come from the highlighted blue zones, better if the x-series implant antenna is perpendicular to the antenna.
Just got the new Galaxy S21; works well with the SIID and the NEXT. The coil is located right in the horizontal and vertical center of the phone so the best reads come at the edge of the phone in the vertical center.
Cat S42: easy read with my IAR M1k. I suppose similar performances with a DT glassie. No trouble at all with a flexM1 of course. Only slight downside: the antenna is in the middle of the back of the phone, not at the edge of the case. So it’s not as easy to find the sweet spot. But the case’s shock-absorbing ridges at the back help you to locate it by touch.
Ulefone Armor 3W: easy read with my IAR M1k and no trouble with my flexM1, as you would expect. The sweet spot is somewhat difficult to hit though, the back of the phone being essentially featureless. Also, surprisingly, it is quite a different sweet spot for a glassie and for a flexie.
To be honest, I didn’t think about mapping out where it is exactly. I was more busy neutering Google and reinstalling all my stuff in the new phone, which always takes a mighty long time if you’re as thoroughly paranoid as I am and you don’t use cloud backup
I’ll use my xLED and my test NFC glassie later today to find where the antenna is and I’ll post a picture.
Speaking of neutering Google, fun fact with Android 9 and up: boot the phone without any network (so it doesn’t get any update of anything you don’t want right off the bat), go to the settings, remove all the Google bits you don’t truly need, remove all the permissions from all the remaining Google apps that don’t truly need it, and you’re left with a phone without a soft keyboard. That’s happened to me twice on two different brand new phones now. Amazing the length Google goes to to ensure you leave shit you don’t want running.