I’m not that experienced with http(s) hosting, but for the two sites I host, I used Certbot with nginx. It seems the combination of the two does the same thing as caddy which was suggested a few times.

So you could either install certbot and point it to your working nginx http config (then certbot will try to get the ssl certificates and modify the nginx config so it works for https and https connections are preferred) or ditch nginx for caddy.