This is totally normal. Expecting your birds to take to you on a timeline, act exactly like "other budgies" you've seen or read about, or assuming that because they are still afraid of you after a week they must not like you are all mindsets that are going to set you back while taming your little ones
It's perfectly reasonable that they're still scared. My girl was skittish for months, and now I've had her for six years and we have a very strong bond with each other.
You need to take a step back. You did all the steps correctly, just a little too fast for them
Since they're still so afraid of you (again, normal), I would go all the way back to just putting your hand on the outside of the cage as much as you can every day and talking to them softly, singing to them, reading to them, etc. Eventually you will see that they no longer shy away when you approach them, and then you can continue - putting your hand in their cage as far away from them as possible without moving it while praising them and talking to them, then a little closer, then a little closer, then finally offering millet from your hand, etc. All of these steps could take a month or they could take several months, it depends on the birds.
It's important to be patient, and eventually they will trust you
Best of luck with your little ones!