Does Hestia DNS Cluster require Apache?

I want to configure a Hestia DNS Cluster.

The following is written:

TIP
If you have just set up your slave, check that the host name resolves and that you have a valid SSL certificate

When installed with the following options,

Configure options
bash hst-install.sh --apache no --phpfpm no --vsftpd no --mysql no --exim no --dovecot no --clamav no --spamassassin no --interactive no

Can I enable SSL certificate without Apache?

Or do I need to install Apache?

yes

no, you can also use nginx only which makes anyway more sense for a dns slave.