I have been playing on a yamaha 6345HG for several years now and I like it, but it does not really suit my playing style. I am a classical player and my strengths are tone and vibrato on long flowing melodies. The Yamaha has a large bore and a powerful sound which I like, but it has a very dark sound and is very heavy and not nimble at all. Vibrato comes out alright but not great.
I have been looking mainly at bach strads, but the problem is they they are almost all medium large bores and I really need a large bore because anything else feels backed up with the amount of air I put through the horn. I want a trumpet that can really sing the melodies if that makes sense.

I want a new or used trumpet that has
Large Bore (.462)
Bright sound
probably silver plated since that adds to the brightness
light weight, but can still handle range and power
nimble

please post a ballpark price range with suggestions if you know it
thanks

There is almost a war over the nature of materials in a build. Frankly when scientific measurements are taken and double blind testing in place a brass trumpet and a silver trumpet will have no differences. There have even been experiments in which a bell was turned from wood and experts could not tell that any changes in sound were made when the wooden bell replaced the metal bells.
The real reason that brass and silver are common in the industry springs from the fact that both copper and silver tend to kill germs. Horns can get a nasty smell if other materials are used. So it is not the sound but the odor that is the underlying issue.