I also use 64-bit Raspbian Bullseye on my Pi4 but my Debian ver is 11.5. I have No issues with piaware-web which I installed from same repository as you did. No issues when I see piaware-web at IP-OF-PI (without port number).
Instead of http://172.16.17.106:800/, try following address in your browser (without http:// and without port number)
172.16.17.106
If problem persists, clear browser cache and reload browser
imaged a spare microSD card with above 64-bit image, installed 64-bit pre-built packages of piaware, dump1090-fa, dump978-fa, and piaware-web from my PPA at Github https://github.com/abcd567a/rpi/blob/master/README.md
I have managed to resolve this issue.
Nginx was running on my Pi4B on port 80/443 and for some reason, the config (50-piaware.conf) was being installed in /etc/lighttpd/conf-available/, but not being activated in conf-enabled.
Once I fixed the port issues between lighttpd and nginx, I linked this file and restarted the daemon (I guess it’s called 'service; in Linux lingo) and everything is now okay.
The biggest problem seems to be myself here - being more competent and comfortable with Apache than with lighttpd and nginx