Libertarians against tax credits is a new one.
Um we had the largest yearly decline in child poverty thanks to it. It seems a bit myopic to ignore the effects of current poverty on children's long-term development. And the families that received it spent it on basic necessities and education for the most part. In a world of government policy that is often ineffective or worsens things, this looks like a winner.
Also the concerns over employment harms are extremely overstated. The real-world evidence doesn't support the concerns. In some cases, the credit even helps families work more.