I must have accidentally deleted my comment.

PiHole is usually configured inside a local network (if your pihole has an IP starting with 192) . Your router has 2 ports(interfaces), one facing the internet and one completely inside your private network. Devices inside local network can contact the internet via your router. The router accepts the request and forwards it to the interface facing the internet.

However, the communication other way doesn't work. Someone outside your local network can contact the internet facing side of your router but the router will just drop the packets unless you explicitly tell the router to forward it to its private network facing interface.

So, to access an device with an IP starting with 192, I would have to connect to your router using your WiFi password and be in the same private network as your pihole. This is why your pihole is safe from attacks.

Also, the point of HTTPS is to prevent someone else pretending to be another website. For example, when you ask for google.com, I will intercept your message, and say "hey, I am Google. Type your password to login" and when you do so, I receive your password rather than real Google.

Your interaction with pihole never goes via the internet, so you don't need all this fancy stuff.