They have: nextdns.io
There was discussion a few days ago: https://news.ycombinator.com/item?id=20012687
There was discussion a few days ago: https://news.ycombinator.com/item?id=20012687
There's a certain level of trust when I use 1.1.1.1 or 8.8.8.8. I'm unwilling to take the risk for this solution. I'm not sure what would help in the trust department to legitimize a solution like this.
Route hijacks can happen to anyone, even Cloudflare or Google. If anything they're more likely to be targetted than a smaller player like Nextdns.