"We provide a variety of DNS records including A, AAAA, CAA, CNAME, LOC, MX, PTR, SPF, TXT etc as well as web redirect and offline actions. Wildcard alias as well as individual IP address updates for aliases are also supported. "
Safety is not a binary value [absolutes don't exist].
I'd say on a scale from 0 to 10 [higher being safer], that's like: 3.5
[which might be more than enough to secure a home system]
I still have the feeling you don't fully understand how it works.
It's also a little bit confusing to have two threads on the same subject open at the same time.
At the Let's Encrypt side, there is the ACME protocol and the ACME protocol currently has three challenges, among them the dns-01 challenge type.
To complete the dns-01 challenge, a TXT resource record needs to be added to the DNS zone with a specific label (_acme-challenge). This can be done manually or automatically, where the latter is prefered.
To do item 2 automatically, the DNS provider would need to offer an API to add (and delete) the TXT resource record.
Also, for item 2 to be automatic, the used ACME client would need to be able to "speak" the API offered by the DNS provider.
im going with dynu DDNS and ive seen they offer the API feature for DNS challenge for use with ACME so giving that a shot and let you know the outcome
just trying to figure out how to add the DDNS service for dyno into my opnsese as they havnt got the service for dyno provider so going to have to specify it as a custom service