As I said earlier, mix feeding can work well for some people :)
However, it can affect your supply. Also babies find formula sweeter, easier, and more readily available (no let down), so they can develop a preference. It can get into a cycle where giving formula affects your supply, baby finds it more work to get milk, prefers bottle, bottle give to stop the screaming, supply affected more.
I was one who after a couple of bottles of formula baby completely refused the breast. I had to either struggle to get bf re-established, or switch solely to formula.
You can never tell whether mix feeding is or isn't going to work until you try it, though, so it's a risk you take.
So, if you really, really want to keep breastfeeding, I wouldn't try it until you're ready to stop if you're forced to. If you are mentally in a place where it's no big deal if you end up on bottles, give it a try.