Give them about 32 hours of work a week and 8 hours of tutorials on other things. Build them up from there.
I still lose about 35% of them. A combo of firing for lack of ability and the devs getting upset and leaving when promotions and raises come slow. Because the ugly truth is a lot of the bootcampers hit a plateau. I have had a couple push through to my bar for senior, but most cap out in my mid range.
During the shortage the ability to hire and get solid mids out of 65% of them was a net positive. Right now though it is less important given the talent coming into the market.