I've recently had Jon build a neck and assemble a P bass for me, it turned out way better than I could have expected. Seeing all these is making me want to get a full build at some point.
Wow that's lovely and I can imagine how good it is.
I have a Shuker neck on a P bass partscaster that he also assembled and set up. Absolutely sublime instrument.
Personally I'd keep the Jazz. It sounds like you're just bored.
T-birds are cool, but have terrible ergonomics and are less versatile.
The other two are Jazz adjacent.
I'd definitely recommend speaking to Jon. Like I said it worked out basically the same price as a similarly spec'd Warmoth guitar neck. The only downside really was the wait.