I was thinking about it as a arrival from the US. Since you go to customs you will have to clear security. They have however a connecting flight route that avoids going completely outside. It’s not as quick as the old setup but we made it in about 10 minutes last time. Have your JetBlue boarding pass handy to show on your phone. Basically all it does is avoid needing to show portal documents for Puerto Rico.
This was our exact experience last November.
The PR portal is no longer. The experience is back to pre-pandemic. After immigration/customs, you follow the signs and end up back by the ticket counters where security is located. TSA helps dramatically here. I went thru on a Tuesday morning; TSA-precheck line was 5 minutes; general security was probably 45 minutes.
