With all of your specifications, you might enjoy building a keyboard yourself. I'm biased towards this route as I'm taking it myself, but it really lets you get everything you want (except the multiple USB thing, I'm not sure how you would do this). I am a programmer, though, and I wouldn't recommend this if you aren't.
When you find a board you like track down the vendor and buy it or pre order it. Honestly it’s not that hard to put together yourself but if time is an issue I understand.
If you decide not to build it yourself find a good local builder. I did this at the beginning through a local Facebook group. They often have twitch/YouTube channels which showcase their work.
Most boards are USBC at the keyboard side and support removable cables.
I would stick with HHKB layout if you can or a 60% layout that supports a similar layout. You could go 40% layout but for me it’s too much mental gymnastics for symbol characters. Get an extra hotswap PCB so you can easily swap out the keyswitches or if the only option is a solder PCB turn it into a hot swap board with mill maxed sockets.
Try and get something with a similar typing angle to the HHKB. Get an extra backup PCB as well.
I grew up on an IBM Model F (I can't believe I let that thing out of my sight, it's probably worth more than I am now), and spent about a decade using just whatever. That thing just felt and sounded wonderful (to the typist at least, I imagine it annoyed my siblings).
When I decided to get something a little more customized to my situation the HHKB hit a lot of the high notes: good, solid tactile finger feel, distinctly audible but (barely) quiet enough to use in an open-plan setting, and a factory no-keycaps option (part of the transition was to break myself of anything but full high-speed touch-type). I had used some Das stuff and it was ok but never really clicked.
I still love these things, and through moves etc. have accumulated a few, but I'd like to indulge myself in something truly tailored to my specific preferences, especially on connectivity, build, and aesthetics.
The HHKB layout is damn-near ideal for a QWERTY-heavy-chorder like myself, but I think I could live with a slightly smaller footprint, it's got a small but noticeable margin for error in excess of what I need anymore.
Ideally I'd like something with multiple USB options, A and C at least. I'd love something heavy, maybe machined metal as a base. And I'd like to stay in the ballpark of the Topre keys on the HHKB. I don't care about `CTRL` or `META` on the right, and I would probably prefer a `SHIFT`, at least on the left, that's the same size as the Sun-style `CTRL` that I have instead of caps lock.
If I've got a few bucks to spend having a real artist put something together that will retain scope for me to tinker on going forward, who do I go to?