Grandma and her iPhone

I need some help.
I recently discovered that my grandmother paid around $400 for various app subscriptions. 😱🫠😭 She plays all kinds of games like puzzles, Yatzy, etc., and listens to “her stories” on YouTube. So she uses her phone a lot, but she doesn’t really know what she’s doing on the World Wide Web. 🥲🫣
I know it’s important to her to stay connected and play her games, but I’m getting more and more worried that she might end up in real trouble. 😑
I just learned about Assistive Access. What do you think? Could this be a good way to reduce the risk?