Behavior issues, dogs won’t stop barking and fighting over toys

So my friend (she doesn’t have Reddit which is why I’m asking for her) has 3 dogs the 5 year old German shepherd is a well trained dog, doesn’t pee, shares toys, doesn’t bark is overall is a good dog. Her new dogs who are 7 months old coonhound+ Australian shepherd mix both girls not yet spayed (she has an appointment booked it’s just the clinic is overbooked rn so it’s hard to get an appointment) the two of them are constantly fighting over toys which she has over 50 different toys for them and sometimes they will want the same ball even tho there’s another ball just like it already out. When one has the toy the other starts to bark and wine and then they fight over the toy. Again most of the time she has 3 of the same toys out for them and even bone treats but they always want what the other has and sometimes even try bullying her older dog out of his toys. They also just wine a lot in general which has been causing some anxiety to the older dog. She’s always try’s to buy multiple of the same toys, give them equal attention she also mostly works from home so she’s around them quite often , tried using a firm voice to tell them to stop etc. She’s looking for advice to stop the toy stealing behavior mostly and keep the winning to a minimum.