Firstly, the VERY good news is that there are plenty of poos, Mallow is popcorning and moving around.
She is also mostly eating on her own as she is not losing the kind of weight that you would expect from the small amount of syringe feed; you are still very much within the safe range so shortly after a big operation.
Secondly, have you tried syringing mushed up pellets? Many guinea pigs don't like the taste of recovery food. Mix some probiotics into the pellets. I find that I have more success with syringing familiar tasting pellets. If you are worried about hydration, make them up a bit runnier. Sometimes, a little syringe food is stimulating a piggy into eating on its own. Perhaps you have some tasty fresh greens (lettuce, spring greens, spinach, carrot greens, dandelion, grass etc - thay also contain lots of water) ready to give her on your lap and see how that is going down together with some syringe feed? Give her lots of praise and encouragement.
Thirdly, you could consider trying poo soup if you have got a healthy companion that is not on antibiotics. Soak some fresh poos in a little water and then syringe the water. This additionally helps to re-stock the guts and mimics natural behaviour. It contains all the "right" stuff - including gut bacteria.
It is a bit of a toss up whether operations drugs, baytril or remaining soreness are contributing to her appetite, but to be honest, I would still be delighted with Mallow's progress if she was mine, considering it is only two days post-op!