I think it's okay to look at the situation both ways. One, you will be able to overcome this bladder infection, and she will do better for awhile. Two, the overall trend is downward, and episodes will come closer and closer together. I read that most dementia patients die of infection. Certainly my MIL did. The question becomes, to what degree do I fight it this time? Bladder infections, of course. Bronchitis, of course. Toe infections, of course. Lopping off of toes? Um, no. As it was we made the mistake of allowing them to operate on her leg to increase circulation to fight the infection. The only way they stopped messing with her was to say "Hospice." Then they could not get out of our way fast enough.
Just know that you have your endpoint, just as she does. When you're ready, consider comfort care only, to be kind and leave her in peace.
Also, dying of infection required a lot of painkillers. Had my MIL been willing to let go before then, by stopping eating and drinking, it would have been a blessing, according to hubby and me. Caring people can (and do) disagree on that.