Even if you are not happy with the work at your current team, does it make sense to continue to stay with current team because you understand the stack better and it might leave you with enough time outside of work to prepare for interviews or should you switch internally first and see if you can find better work ? Kind of at crossroads right now.
Both makes sense depending on the opportunity
I would stay at the current job and prepare for the interview.
Prep for both. Sometimes it's super easy to transfer to same role in company since they don't reinterview. But if you have to reinterview anyways, look externally as well.
I once switched teams for 3 months. It was fun. The team was happy to have the extra help. I learned a lot about their product that helped my other team synergies with theirs. If you have a richer relationship with your company than just a cog, a lot of organic opportunities can happen.
Move out