It isn't like qanon, and it isn't a conspiracy theory, but CRT contains a lot that is bunk.
What we are witnessing with these laws is a reactionary backlash which was largely spurred by the 1619 Project. CRT has been taught almost exclusively at a college level, but 1619 is aiming to bring it to K-12.
As a reminder, 1619 contains a large number of historically questionable assertions. Example: a claim is made that we went to war with Britain because it had recently banned slavery in the UK (but not in its colonies), and hence we went to war to avoid the banning of slavery. There is just one problem with this claim: there are zero writings - books, newspaper editorials, pamphlets, flyers, personal letters - giving this as a reason for the rebellion. While there are plenty of writings giving other reasons (e.g. "taxation without representation").
The truth is that slavery was already non-existent in the UK proper. So they banned it in order to claim a moral high ground but left it legal in their colonies because they were profiting from it hugely. Cheap cotton and tobacco - they weren't about to ban it in the colonies any time soon.
I don't like conservatives mucking around with course curricula and creating a chilling effect on instruction in schools, while trying to push their own ideological agenda for lessons in "patriotic history." Also, notice they haven't banned "lost cause" pseudo civil war history.
1619 - like defund the police - was another unforced error on the part of the left. It isn't historically sound. It's politicized history. It doesn't play well to the general public. And it's giving the right an excuse to exercise its own authoritarian tendencies.