I bought second hand an AT&T SM-986U unlocked. Phone. The seller switched to Verizon, and it worked for him. When I got it it booted up as AT&T, only one SIM slot amd one SD slot. The box had 2 IMEI numbers so I was suspicious that it does support dual SIM. It turns out the AT&T does not support this phone with eSIM yet. And have not enabled the feature, however, T-Mobile did enable it in the June 2021 update. So using ODIN the latest version I was able to re-flush the ROM to the latest T-Mobile ROM. I downloaded it on some site on called SAM something, I don’t remember. Folllowing instructions posted there, I was able to flush the T-Mobile ROM and now the phone has the T-Mobile pink logo when it boots up and is all T-mobile and still unlocked. Now, the phone model changed to SM-986U/DS. (Dual SIM) and the eSIM option is enabled offering options on how the dual SIM need to be configured. My tray is still a 1 SIM one Micro SD with no dual SIM slot on the tray, so I bought on eBAy a hybrid Dual SIM tray / 1 SIM + SD . I will get it in a few days. I am very hopeful that after having T-Mobile enable dual SIM that it actually has 2 SIM card readers. I have eSIM now on an AT&T SM-986U that is now turned into T-Mobile with model name SM-986/DS. I expect the new tray to work with 2 physical SIM cards, at least I have eSIM as an option now. I do use T-Mobile. I did however read that the Snapdragon version note 20 ultras do not have 2 SIM readers And that the other chip does have a 2 reader. Let’s see when I get my dual SIM note 20 ultra tray.