Female rat blocking the hideout

Hi! I am a new rat owner, bought two cca 5-6w females from pet store a week ago - Eni and Pupi. It was going well, the were not aggressive and would sleep together. Pupi was kind of shy, but very agile and if there was food around, she would even come to my hand (all paws on my palm). Eni had more courage but only went as far as palm as well. Also, she had troubles climbing down from the level with one of the hideouts and water, so I kept everything accessible to both of them some food on ground floor, some on upper levels. I had to leave them for weekend and my friend came to check them out.
Few minutes after my return, Pupi was hiding and Eni was exploring the ground floor, because all remaining food pellets were there. She figured out how to go down, which was great, but when Pupi came out too and tried to grab some food, Eni would wrestle her. I immediately added more food sources, but Pupi was then scared most of the time to go out of the hideout and Eni was blocking the entrance and pushing Pupi further back so she could not go out. If Pupi made it to second hideout, Eni followed her and blocked her there. There was no blood, no loud squeaking, maybe one or two hardly audible squeaks, some aggressive grooming. Could this be hormonal or out of boredom?
Should I block both hideouts (they are fixed extensions to the cage) and give them some temporary ones which have at least two entrances each so Eni is not able to corner Pupi?
I am planning to start their playtime outside of cage as soon as possible, but none of them likes to be handled yet and I assumed it would be best to first let them be comfortable with picking up by hand so they are not trying to escape. I know I have made a mistake and should not let them be alone for two days. Also I am not sure if this behavior is within normal establishing of hierarchy or is it too much?

They are babies. Babies play. A lot. Sometimes it looks like they are being mean, but as long as no blood, or fur flying, they should be ok. They are still really young. I'd give plenty of hides, and play toys. Power grooming is normal at any age. They will work out dominance as they get older. But plenty of hides and toys is good for now.

Thanks a lot, you calmed me down. I added some toys but I cannot imagine much more of them. They fought today as well, but they both seemed ok, even groomed themselves shortly after. Only odd thing - Eni tried to mount Pupi a couple of times (they are definitely both girls).

We may think they are fighting when in fact they are playing. Young rats play hard.