Thank you for taking the time to investigate. It seems like there are several tools that have successfully implemented DNS-based Let's Encrypt challenges and DNS-based automation for deSEC.
If the higher TTLs really are a problem, could it be possible to just restrict the usage of deSEC to wildcard DNS + Certificate usage (wildcard A/AAAA record + DNS challenge for Let's Encrypt)? These records only need to be updated very infrequently if at all. I personally run my cloudron instance behind a VPN, which is why I am unable to use the HTTP based verification.
deSEC is a very special provider that I think is worth putting the effort into supporting. AFAIK It's the only donation-run/free, European provider with DNSSEC support currently included in Cloudron. Hetzner doesn't support DNSSEC. It's also (likely) one of the most privacy respecting providers available.
I have also made a post on their forum. Maybe some creative ideas will come about.
