Hi Ed, thanks for finding the bug. This was recently introduced by some changes I've been making for large scale projects.
I've PR'd a fix here: only create standby proxy if it is configured by snopoke · Pull Request #26126 · dimagi/commcare-hq · GitHub
If you're setting up a monolith you could just update the code in /home/cchq/www/<env>/current so that you aren't blocked until the PR is merged and then re-run the Ansible playbook.
Alternatively if you wait for the change to be merged it should get picked up when you re-run the playbook (assuming you're running it with -e 'CCHQ_IS_FRESH_INSTALL=1'.