I've travelled down the rabbit hole such that I have an Ergodox EZ and am in the process of building a Dactyl Manuform clone. I really can't comment on more typical non-ergo boards (but if you're interested in ergo, I highly recommend the Ergodox EZ). As your reply's parent implies, it's safe to stay with your current switches and focus on trying a board that has QMK (they're a very popular switch that balances weight/travel/actuation/tactility/sound). IMHO, firmware is the real magic with mechanical keyboards.
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.
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.