Hi
I have been in the exact same place as you not so long ago.
Shure has a very specific house sound and if you loved your 535 I can assure you of one thing, you will adore the se846 if you can afford the price tag on those babies
The fit is somewhat even better to me despite them being a bit bigger and the sound is outsdanding if you know how to EQ correctly.
I'm having a bit of trouble with people listening to music equalized flat since it is absolutely not how it is intended to sound by the artists but how it is made to play without distortion on any given device.
live shows are fun, dynamic and powerfull that is to me how music should be played.
That said I have bought the Campfire Vega and JH Audio 16V2 pro customs too to compare to the se846 when my se535 failed.
The jh16v2 are in a league of their own but to me the se846 are way better than the Vega.
They can handle so much and so well that it is very impressive. People saying otherwise either have different tastes and I can dig that or just don't know how to properly drive and equalize their music to make the earpieces sound like beasts.
The Vega have a manufactured drop in the middle section of the spectrum that simply cannot be overcome even with the best equalization. They are to me way less fun than the se846 though the bass response is just as great.
I'm a bass head myself but when you love rock and metal the rest of the spectrum counts as well and they simply can't match the se846.
Like I said the JH customs are in a league of their own. They're just as powerfull and dynamic but are more natural sounding with less emphasis yet a very nice representation of the middle section of the spectrum.
Better seperation is also very apparent when plugging them to the Chord Mojo compared to the se846.
I can't speak of the Orion and Polaris since their bass presentation is too light for the bass head I am but one thing I know is that when you need bass even if you're not a proper bass head your iems better be able to produce them.
So overall if I had an advice to give you I would go with the se846 since you are already familiar with the shure signature, you can not be disappointed there. Now I understand that campfire also has the andromeda that is kind of a do it all but do it outstandingly good IEM so you might as well take a look there.
Cheers,
Jordan.