Aldoo
Ergo keyboard enthusiast.
Daily drives a couple of Dometyl generated dactyl keyboards (3x6+2+6 keys per side), using Optimot layout.
I am currently using thumb shift on all my keyboards as it feels very natural: no need to move the whole hand (unlike classical shift) and no priority conflicts (unlike HRM shift: with HRM, if hold is preferred then you shift letters by mistake, if tap is preferred you end up typing erroneous extra chars instead of shifting).
Actually I combine enter and shift on the same key, giving priority to hold/shift. Since I don’t need to roll enter, there is no conflict.
Funny, it reminds me of one I built in 2022:
Not currently available, and the budget is not yet known, but it checks all your other criteria (except the travel case): https://x-bows.com/products/x-bows-split-keyboard
Otherwise, you can start with another existing option and adapt it to add what is missing. For instance, if the keyboard is built around a pro micro and you want to make it wireless, you can replace the pro micro with a nice nano and find a way to place a battery and power switch.
It looks like a MoErgo Glove80 to me.
I learned about thunder in this thread today, but i have troubles figuring the UI even for basic things. For instance, how do you reply to a specific comment? (I can only see this icon in the lower right corner, but it does not look like it will do anything else than creating a first level comment!)
What is wrong with it? What are you looking for?