Kids Fire Tablet access issue

[DSLiverpool]

When I set up my girls fire tab it asks for our main amazon log ins and the tablet mimics our main options but with a “fire for kids” app.
She has a profile and I just want the profile to be her stuff not open options.
I’ve tried parental controls etc but from turn on it wants a main pin and then give her access to everything.
My boys set up no issues so this is killing us.
Any help appreciated - I’ve reset it awaiting trying again.