No, that's a public CA. No public domain registrars will be allowed to sell .internal domains so no public DNS servers will resolve .internal and that's a requirement for let's encrypt to validate that you control the domain. So you must use a private CA (one that you create yourself, with something like Smallstep, Caddy, or OpenSSL commands) and you'll need to install that CA's root certificate on any devices you want to be able to connect to your server(s) that use .internal