Hi, welcome to HC
What you're describing sounds like pretty normal robo behaviour to me! They're a lot more skittish than other species of hamsters so they are a little more on their nerves and are more inclined to being a bit weirder. Their memory isn't amazing either so they can sometimes forget that you're a nice human and go into a flighty sort of mode and freeze up, or just flee for their lives. With robo's everything from approaching to taming is going to be done slowly
Bar chewing can be a behavioural sign that they're bored or don't have enough space. What type of cage do you have, and are you meeting the minimum requirements? Have you tried to give them a lot of digging room, and maybe a whimzee dog chew to occupy themselves with? Hides, and tunnels can mentally stimulate them a bit more too. Flora really loves a ceramic mug we've put in her cage, and Mallow really enjoys having a slightly elevated nest box for gerbils.
For the most part, it sounds like you're doing pretty alright