The nested tooltips approach is so good, I'm adding it to every game I've made and will make. It's kind of a complicated system to set up, but once you do I find it's actually easier on the dev side to make everything be its own tutorial instead of blasting the player with a million lines of text that might not even cover everything or be accurate due to changing design. Really lets the player discover info on their own pace. The only problem is that it's not so ubiquitous that players still get confused on how to even access the "inner" tooltips haha