I am not much on networks, but could you use a ping script to locate it? This is what I tried for my network address. Depending on you network, 20 is enough for me, you could also use a shell script to loop through the ip addresses get hostnames, `ssh 192.168.0.3 hostname`.

    pi@RPi5:~ $ time for x in $(seq 2 20); do ping -rc1 -W1 192.168.0.$x | grep 'from'; done
    64 bytes from 192.168.0.2: icmp_seq=1 ttl=64 time=1.31 ms
    64 bytes from 192.168.0.3: icmp_seq=1 ttl=64 time=6.20 ms
    64 bytes from 192.168.0.4: icmp_seq=1 ttl=64 time=1.53 ms
    64 bytes from 192.168.0.5: icmp_seq=1 ttl=64 time=0.104 ms
    64 bytes from 192.168.0.6: icmp_seq=1 ttl=64 time=5.69 ms
    64 bytes from 192.168.0.7: icmp_seq=1 ttl=64 time=5.36 ms
    64 bytes from 192.168.0.8: icmp_seq=1 ttl=64 time=1.20 ms
    64 bytes from 192.168.0.9: icmp_seq=1 ttl=64 time=2.38 ms
    64 bytes from 192.168.0.12: icmp_seq=1 ttl=128 time=4.57 ms
    64 bytes from 192.168.0.13: icmp_seq=1 ttl=64 time=54.7 ms
    64 bytes from 192.168.0.15: icmp_seq=1 ttl=64 time=6.31 ms
    64 bytes from 192.168.0.16: icmp_seq=1 ttl=128 time=1.41 ms

real    0m7.292s