2.4 Ghz internet devices keep disconnecting from GSE internet box

I don't know the term "GSE internet box."  But I do have TMHI and can offer some general advice.  T-Mobile calls the unit a "gateway."

1. The gateway needs to receive a strong 5G signal, but it also needs to be in a fairly central location in your house.  You might need to try it in a different room.
2. You want to keep the default network as it comes (with the exception of changing the password.) The default network supports both 2.4 GHz and 5 GHz and the highest level of security available on the gateway which is WPA2/WPA3.  Most devices should work on this, as you found the first day.  Your Samsung S23 should be fine with this network.  (by the way, my Amazon devices work fine with this configuration.)
3. Some Older devices (possibly your printer?) might not like the default network.  So you want to ADD a second network which is 2.4 GHz and "dumbed down" security of WPA/WPA2.  Use this for the devices that won't connect to the default network.
4. Generally, 2.4 GHz reaches farther throughout the house than 5 GHz.   Perhaps your kitchen is far away from the gateway and the appliances are trying to connect to the 5 GHz band of the default network.  You could set up a third network which is 2.4 GHz and WPA2/WPA3 security. 
5. You could have a fourth network which is 5 GHz and WPA2/WPA3, but you probably don’t need it. 
6. Devices on different networks can communicate with each other.  For example, my laptop on the default network can print to my non-Wi-Fi printer which is connected via USB to my old desktop computer, which is connected to the second (2.4 GHz) network.
7. You might need to "factory reset" the gateway to restore the original default network.  This might help your issue with updates.