Who said there will be a JW5? The current director said he plans to do other things, and Reeves himself said he will only return with the original director.

Also the ending seems pretty conclusive with a good story arc for John. Bringing him back would only be to make another movie for money.

I think Mr. Nobody might appear in the JW spin-off the Ballerina to give more context to his back story or why he needed a specific amount of money.

Or they wait to see how he is received and he gets his own spin off movie or show.