Basically you set up an acme-dns server at myacme.com. It has two aspects to it: a TXT-only DNS server and a REST API. You do POST myacme.com/register, and it gives you an "account" with a subdomain, username and password, like for abcdef012345.myacme.com. The username and password let a program set TXT records for that subdomain.
Then you do a CNAME from _acme-challenge.shitposter.world to abcdef012345.myacme.com. Make sure you have an NS record from myacme.com to *.myacme.com to say that your acme-dns server is the authoritative source of records for abcdef012345.myacme.com (and obviously an A record for the acme-dns server itself).
Your acme.sh script will get the challenge from Let's Encrypt and put the TXT record at abcdef012345.myacme.com using the aforementioned credentials. Then when Let's Encrypt goes to check the challenge at _acme-challenge.shitposter.world, it follows the CNAME to abcdef012345.myacme.com, sees and validates the challenge TXT there, and issues your wildcard cert.
They're about the same as anything else in systemd, which is to say stable enough, but too verbose to set up for what it is, and it feels icky in general to use.
I know the feeling, and at least you have it set up. I know people who just say "cron and renew hooks are too complicated, I'll just remember to do it every few months, it doesn't take that long!" And while that mindset isn't objectively wrong, it's annoying and very lazy.
And the ones speaking English speak it horribly, and not in an "I'm trying to learn" way, but rather an "I hate your language and will only put the bare minimum effort into learning it enough for you to sort of understand what I'm saying" way.
Every time I hear some story about Lucifer or Enki or the Serpent being the good guy who just wants to help humanity with knowledge, it sounds nice but then I remember that's also the same one who demands child sacrifice and other unspeakably horrible acts in exchange for said knowledge.