expanding technology access for near adult child

So my daughter turns 18 in January and will graduate from our homeschool in May before she leaves for college next fall. I want to prepare and graduate her to wise technology use and habits. We have been a very low-tech family all along, but she did get a limited smartphone (Pinwheel) when she was 15 1/2 and has now had an iPhone for about a year now. We teach about tools vs toys and creating over consuming. We use Apple ScreenTime, Bark and Covenant Eyes to provide protection and controls on her phone and laptop. She is responsible in many ways (works a job, takes online dual enrollment classes, etc), but she does struggle with impulse control, which we see in many areas, especially in her relationship with food and books. (I know that having an addicted reader for a child may sound like a "problem" that many parents would love to have, but her relationship with reading tends to create problems similar to what you typically see with youth who are addicted to technology use–she consumes books to excess, often choosing to read over sleep at night and sometimes literally all night long, she is constantly seeking for more stimulation, and often uses reading as a way to isolate herself and not have to interact with people.)
We have tried to slowly allow greater technology access over the past few months, in order to help her be able to practice while she is still in our home where we can teach and correct her. It has been a challenge, though, especially with her reading obsession, as she tends to seek out and find places online where she can read fan fiction or other unpublished authors who have put their work online for free. She now wants to get a Kindle Unlimited, and I see all kinds of red flags about that, both from a content and time management perspective. But she is getting closer to being out on her own, and I wonder if it would be better for her to have more technology freedom, so she can test the waters while she is in the safe environment of our home where we can observe and give corrective feedback, instead of her having to figure all that out herself when she is on her own in less than a year. I wonder if we should scale back on the parental controls or let her be the one to manipulate the controls so that she is deciding what they are (but could still change them herself, much like I do). Do you have any counsel on how to approach this? How do we help her to grow her technology skills in the limited time we have left with her at home?