TLS/SSL certificates, DNS-01 challenges, and nsupdate

Probably an edge case, and maybe a good time to learn more about how Hass.io Add-ons work, but figured I’d see if anyone else has a similar setup as me and has come up with a good solution already.

I use LetsEncrypt certificates for all my self-hosted stuff, which I use Dehydrated.io to generate with DNS-01 challenges. My domain names aren’t from any of the big’n’fancy Domain Registrars, and I just use nsupdate to make changes to my nameservers. No fancy API’s here! Unfortunately, it leaves me unable to use the Official LetsEncrypt add-on, as it only supports specific DNS providers.

I’m wondering if anyone has run into the same and made an add-on that can use nsupdate for deploying their DNS challenges? My general searching so far has found pretty much nothing for “Home Assistant nsupdate” and “hassio nsudate”, so I’m not really hopeful, but I thought I’d ask.

I’m a little loath to work out making my own add-on, as I’m under a intellectual property agreement that, which it wouldn’t stop me making it for my own use, would mean I’m not allowed to share it, so it would solve my problem, but not the same problem for anyone else.

(for anyone noting I do throw up posts all the time about configuration of different parts of Home Assistant, I did check, and as long as I’m not identifying who I work for, or using work time and equipment, that is fine, since it falls in the category of discussing how to use other people’s “products”, but not actually producing my own code. I could probably get approval for doing open source projects, but its an arduous sign off process in the first place, and then requires every change I submit to go through the lawyers to make sure I don’t expose internal secrets etc…)

So I know it’s probably in the “too niche” category, but I don’t particularly want to have to renew my cert manually (such as this, but I also don’t expose my Home Assistant to the internet…