I don’t think I’ve ever come across a DNS provider that blocks wildcards.
I’ve been using wildcard DNS and certificates to accompany them both at home and professional in large scale services (think hundreds to thousands of applications) for many years without an issue.
The problem described in that forum is real (and in fact is pretty much how the recent attack on Fritz!Box users works) but in practice I’ve never seen it being an issue in a service VM or container. A very easy way to avoid it completely is to just not declare your host domain the same as the one in DNS.