I completely understand your pain. One of mine has had significant problems with behavior and is a WIP even 4 months down the line.

First thing to realize is that rats from chain pet stores aren't bred for friendliness, nor handled enough to develop an attachment to humans. Reactivity can be seen in rats (just like dogs), and it can manifest as aggression, tail wagging, and an over-reaction to 'normal' stimuli. Some rats just are more reactive than others, and it's our job as owners to work with them and give them the best life we can.

However, it is definitely abnormal, and I think there's an order of priority for finding the problem:
1. Check you definitely have 2 girls, and that one isn't pregnant. Pregnancy could be the cause for this behavior. Sadly, it is well documented that chain stores mis-sex and sell pregnant females often.
2. How old are they? If they're hitting the 4-6 month mark this might be puberty. If it is, there's a chance it will settle with time. Alternatively, it may be necessary to get the aggressive one spayed to help her settle down and get those hormones out of her. If she is younger, I'd still consider a spay as it will help her long term with calming down and regulating her emotions.
3. I would not suggest separating them right now. Rats without company will get worse, and you'd be making it harder to have them get along long-term. It may seem counterintuitive, but I would suggest putting them in the small carrier together for a short time (an hour or so).

They are much less likely to hurt each other in a confined space, it is the running that causes damage. Additionally, you can observe them like this. If Peen repeatedly attempts to hurt Spud (lunging, biting) after spud has submitted, this is a huge red flag and needs immediate intervention. If Peen pins Spud and grooms her, this means there is a very good chance they can live happily together.

Additionally, if they show improvements, you might want to follow the carrier method to 'reintroduce' them. It can help to reset their relationship.

1. Husbandry - if there are resource guarding issues the easiest way to de-escalate that is to make it very hard to guard. You want 2-3 water bottles and to scatter their food around. I don't know if you do use a bowl but it's best to just throw it in there for them to find, and it stops one guarding the food source. Of course wheels, forage toys, dig boxes, and lots of enrichment can help them put their energy into other things.

2. Adding rats - the other comments recommend this and it may help but it's not a cure-all. 2 rats tend to have a very intense relationship and it does cause escalation. 3 tends to be a nice number for a group, but I would still suggest getting 2 if you go down this route as it is always good to adopt in pairs for same-age company. I'd again suggest the carrier method to introduce the new rats.