I think you are doing fine for 7 weeks. My son also much prefers to sleep in his RnP for naps and overnight. We tried the bassinet when he was much younger, and he acted exactly like you mention. He never liked it much.
We started trying to get him in his crib around 6 or 7 weeks. It was a struggle, but after a few attempts at putting him down, he would finally sleep for a few hours at a time in his crib. Then he got a cold, and the doctor gave us many suggestions for helping him be more comfortable. One was to not have him lay flat, so everything could drain. So we put him back in his RnP. He is now 12 weeks old and sleeps in both his RnP and crib. I just returned to work this week, so put him in his RnP for the first two nights, so I could get as much sleep as possible. The problem is that in his crib he wakes up every 3 hours exactly. In his RnP, he sleeps for about 6 hours straight. It is just a transition we need to get through. I don't have a ton of advice for you, other than keep trying. Over time you will be able to get him to sleep other places, but he can definitely stay in his RnP for now. I worry about my son getting too big for his also, but he still loves it for now.
I would definitely swaddle him (at least his legs/lower half) when you put him in a crib or bassinet (while he gets used to it). I think my son likes his RnP so much, not only because it keeps him from being flat, but also because it basically keeps his legs swaddled for him. That is comforting to them. Good luck!