The need of a manual renewal after (less than) 3 months is annoying. For some domain name service providers (e.g. Cloudflare) automatic renewal is possible by using special plugins. On a server with root access there is another possibilty: Install a small domain name server (I recommend yadifa) on this server, delegate the subdomain „_acme-challenge“ of your domain to this server and add a small bash script which will make the necessary DNS updates when you run certbot. On https://github.com/hatzfeld/certbot-local-dns I explain how to do this.