Here some more info to better understand the device
Internal Photos
https://fccid.io/TV7LHG5ACD/Internal-Photos/Internal-photos-3620773.pdf
External Photos (maybe where to open it)
https://fccid.io/TV7LHG5ACD/External-Photos/External-photos-3620772.pdf
The serial console is most likely disabled by default
Some old notes how to enable it
https://oldwiki.archive.openwrt.org/toh/mikrotik/rb941_2nd#how_to_enable_serial_port
Uses same pintout (RX, TX, GND) ?