You can have two domains pointed to the same install.
To do that, have example1.com and example2.com pointed to the same IP.
Then put example1.com in your ~/central/.env file.
SSL_TYPE=letsencrypt
DOMAIN=example1.com
Then in ~central/files/nginx/odk.conf.template, make this change in line 3.
- server_name ${CNAME};
+ server_name ${CNAME} example2.com;
I've only tried this with LetsEncrypt as an SSL type. Your mileage may vary with other types.