Another PiHole pro is that it can work for every device in your house (if you set it up that way).
There are tons of important details to keeping a critical service up and running almost all the time - even if you are competent in this, that is still time every month making sure it's running, secure and functional.
The only reasons in my opinion to DIY a solution would be a) learning, hobby or for fun or b) you have requirements that can't be met another way, like privacy goals.