Need advice: Navigating tricky internal mobility situation

Long story short. I recent moved internally within  groups (product -> product) this past summer (been in new role for ~6 months) after previously doing two years and getting strong reviews. The new role is much more stressful and time consuming than I thought, and I find myself constantly worried about the job and unable to relax. I feel like I’m not learning a lot in the role and feel like a lot of the problems I had with my previous role are even more apparent now. 

I’ve looked at some different roles within my bank (non-IB) and have had some very good networking chats / interviews, with some teams asking me if I wanted to go through more formal hiring conversations with senior team members. However, my bank currently has a one-year minimum requirement in current role before you can move internally (worth noting that this can be waived with a manager exception and I think has been done before). Therefore, I’m nervous to proceed with some of these other internal opportunities as I’m worried 1) my current team would block it / make me wait and 2) the other team would rescind the offer. I think it’d be more likely that my manager would grant me an exception if I had a genuine conversation with him first, but I also don’t want to reveal my feelings until I have an offer in hand.

Curious on if there’s any thoughts on how to best proceed? Do I gamble and sit down with my manager and tell him the role isn’t for me even before I have another job internally in hand? Or do I just proceed silently with these internal opportunities and wait until I have an offer for my current team to find out and risk a very negative reaction since they’re blindsided? I will say, my bank has always had a pretty friendly mobility policy, and when we’ve had juniors quit for other firms before, senior members have always said to talk with them first and find solutions internally before looking external (realize they could be just saying that). In that case, would it be possible for me to “bluff” and say I would leave the firm if they didn’t let me move (or something a little less extreme along those lines).

Any advice is appreciated!!