Can't accept pgbouncer 6432 port on PostgreSQL server
Your PgBouncer is not listening on IPv6 address because this line tells it so:

listen_addr = 127.0.0.1


You should change it to something which includes IPv6 addresses, like

listen_addr = 127.0.0.1, ::1


or maybe (to listen on all interfaces):

listen_addr = *


Side note: you should probably not publish your real addresses, even if  "440a:90a0:302:4525:lda0:1:2:3" is not a valid ipv6 address :-)