P.N.
It is absolutely normal for breastfed babies to wake during the night for nursing. This might be her new normal schedule, though she had been sstn. It is also normal for all babies to go through different sleep phases so even if they are sstn, that may not be forever. There is a lot of growth going on and she needs the nutrition now. As others mentioned teething may also be contributing, of course.
Breastmilk actually provides more nutrition and calories than the solids she would be consuming at that age, so adding solids to fill her up may be counterproductive as it may fill her up but may not satisfy her nutritional needs so she needs to get them met later.
She also may have some intolerance to what you are feeding her or her body just needs to get used to digesting it, so it may be impacting her sleep. So I might give her the solids earlier in the day and concentrate on extra breastfeeding in the evening.
You may not be able to "fix this." She just might need the feeds at night right now. I'd try to get her to nurse more during the day. At that age they are really waking up to a lot of what is going on, so she may just be more interested in the world than nursing during the day (thus starving herself and making up for it at night). Maybe you could try nursing her in a darkish room with no stimulation? It might be helpful to call a LLL leader to talk through it, they often have good suggestions. Sounds like CIO is not working for her, so I'd let that go.