Thanks for pointing me in the right direction.
After searching the forum and reading this and other threads:
I determined that I had the incorrect serial address in the bridge set up. I used the dmesg | grep tty on my Pi4B, which showed the correct serial address, in my case
openhabian@openhab:~$ dmesg | grep tty
[ 0.000000] Kernel command line: coherent_pool=1M 8250.nr_uarts=0 snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 smsc95xx.macaddr=DC:A6:32:82:41:2E vc_mem.mem_base=0x3f000000 vc_mem.mem_size=0x3f600000 console=ttyS0,115200 console=tty1 root=PARTUUID=0522baae-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
[ 0.001812] printk: console [tty1] enabled
[ 1.438687] fe201000.serial: ttyAMA0 at MMIO 0xfe201000 (irq = 36, base_baud = 0) is a PL011 rev2
[ 3.177768] systemd[1]: Created slice system-getty.slice.
[ 5.933131] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device
[606792.874156] cdc_acm 1-1.1:1.0: ttyACM0: USB ACM device
[606879.778072] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device
Now I’m ready to try my first Z-Waze device when it arrives later this week.