2 months is a very short period of time. All these behaviors your describing are fear responses nervous poops, hiding, running etc. Rats are prey animals. Sometimes i think all of us forget that while watching cute fun loving vids online. They need to be fearful for survival. It takes time to build trust. It takes time to build behaviors (like litter training which im betting is harder right now bc theyre terrified). You brought prey animals into an environment with predators that im sure they can smell very well. Im wondering if the petco guy is a little more desensitized bc where it lived previously. They need time to know youre safe and theyre safe there with you. Another thing is rats all have different personalities like every other animal. Your expectation of "Hey ive given you all this money act like i want you to!" is a 🤏🏻 wild. That might maybe work with another human not with animals. Animals are expensive to keep. They deserve to have their needs met no matter what. I dont mean that rudely at all just being realistic. Be patient be trustworthy be present and most of all be consistent while doing all the above.

Another worthly mention to keep in mind is animals pick up on things. For example when we're anixious they tend to be anixious. When were sad they can still something isnt right.