But that would require upgrading to Ubuntu 20.04, which is a major operation in its own right. And it's not as if snap is without problems of its own.
I use acme.sh with dns, it just plonks a certificate in a directory of your choice and runs a reload command of your choice. I actually upload the certificate into a kubernetes cluster. All repeated by cron
Tried doing the same with a Ubuntu 14.04 server. That failed totally while installing snapd on it, which replaced existing upstart init system with systemd. This caused no services to start on next reboot.