Some general background about DNA work--source on this is a conversation I had at the end of 2019 with someone from the MA forensic labs. I asked her general questions and she gave me general answers. There's been a lot of progress since then so much of this is probably outdated.
In many states, LE either is required to only work with accredited labs, or prefers to do so. The work from an accredited lab can in most cases be taken directly to court, or used for legal identification. Other labs are considered investigative tools, and any results have to then be confirmed through formal channels. There are privacy issues, too. In most states, there's an approval process required to use outside services, and that can take a couple of years to get through. In Florida, for instance, you used to have to show that you had exhausted all other investigative options to justify the privacy invasion (though I'm told that may have changed recently).
Accrediting is usually on a state by state basis. A lab that is good to go in Massachusetts (where I am), for instance, might not be accredited in New York State, or vice versa. Last time I looked, there were at least two professional associations for forensic genealogists, with 70-100 members in each (some overlap). A local case where they needed genealogy services had a choice of a couple dozen agencies that were accredited in Massachusetts. But only two of them had room to take the case. The others were all backlogged several months to years.
This doesn't even get into the issue of who pays for it. Besides multiple agencies usually being involved, many LE agencies aren't allowed to accept outside funding. And that usually requires multiple cycles of funding approval after you've obtained permission to do the work. In Massachusetts, it can even involve getting a special legislative appropriation.
I don't know how or whether any of this applies to Texas, or to WCJD's agencies. But I thought it might help people understand some of the things that could be going on.