So with them first showing her chart readings being iffy when she came out and now with the comments of her DNA being changed, she definitely gets her powers in this series. The hex changes whatever and whoever it is to meet Wanda's setting/criteria but I think with
enough energy from the "Hex" and
one's own willpower/ desire they can use said energy themselves and grant themselves something they want. Remember the kevlar vest even though the hex changed it to Monica's clothes in the hex world still retained its bulletproofness when it came out even though it changed forms. At its core that's what it was, a kevlar vest made to be bulletproof (even if it came out as a balloon or ice cream it would still retain its core as Kevlar and be bulletproof). I'd wager humans are different since we can think and grow/ evolve so our cores can change and be different (plus this is a superhero show, need some comic book bookiness etc)
One of the twins copied Pietro's power because to them he was a cool uncle (though the twins may be an outlier as they can do whatever they want such as age up and resist wanda, but let's say they follow the above rules and conditions of hex energy and desire/will) and the other got wanda's abilities. So Monica herself has the hex energy already but no known desires, yet. Honestly with the captain marvel drops I bet Monica's inner child will come out and she still wants to be one of her two favorite heroes, one was her mom who you can say she definitely became like and the other Carol Danvers. So when that final condition of will and want come (maybe the finale or when the real big bad shows up if they do) she transforms into a copy of captain marvel
....
*Hex energy can give you powers* basic summary for those who ain't wanna read this long theory of mine
./SPOILER]