Other works a default situation is:
USB port works but not work slot 1 with his SIM1
LTE works in slot 2 always but you must select what sim slot you use 2/3.
and you can resign from USB port to enable Slot 1 for LTE purpose with SIM 1 and if you place modem with USB3.0 interface then you should mask/isolate to ensure correct initialization of USB3.0 pin's. Check the documentation and many posts at forum.
https://forum.mikrotik.com/viewtopic.php?t=153205