CDMA gone after May 31 and phone consequences

I’ve been a Sprint customer for over 20 years, and now after their union with T-Mobile, I’m being told that my old Galaxy 6 and it’s CDMA technology will be dead after May 31 (this date has been moved multiple times). However, my wife’s Galaxy 8 which also supports the same technologies (CDMA,GSM, and LTE) and was not flagged as obsolete . I only use a cell phone to make or receive calls (mostly from home) , so the LTE connection is all I need. I realize that the Sprint RF band 26 that my phone uses  will probably be replaced by one of the T-Mobile bands, and, I’m wondering if my phone will even be compatible with a T-Mobile sim card ? (my wife’s Galaxy 8 is working fine with a T-mobile card). T-Mobile’s first tier contacts never answer these questions , but show considerable interest in locking me into a long term contract by offering  a credit carrot for a less than popular 5G phone. (I have no use for 5G). If T-Mobile would just tell me definitively (in their broken English) that my old Galaxy 6 phone is absolutely incompatible with T-Mobile’s sim card and network, and I will not be able to receive 4GLte signal after May 31 regardless of whether CDMA goes belly up.