Fulcrum VS unk

dude I really think you should consider a sideways-mounted 5-way switch for the thumbs like I did on the fulcrum. I think it would work really well on this form factor

You may be interested by the 40-key version of the Fulcrum

It's tough to use more than 2 or 3 regular thumb keys. Check out the Fulcrum for max ergo thumb functionality

I use 20 keys as my daily driver and it’s been a dream come true. My RSI disappeared and as a bonus I type faster than I did before on regular keyboard.

Fulcrum allows you to use one of the thumb joysticks as a mouse, though i wouldn't recommend it as a full mouse replacement

Although, I guess you could also go with your idea with using one hand for the vowel and one for the consonant and use just two 5way switches. There is actually a DIY keyboard with two 5way switches: https://github.com/dschil138/Fulcrum I think it would work well for kana input.

I think you would really like the fulcrum

I doubt this will be what you are looking for but I did the same thing with the keylogger and had the same realization, which heavily informed my keymap and hardware design on the Fulcrum. Full keymap is at the bottom of the readme page. Also if you go to my profile I have a pinned repo on key press stats that you may find interesting.

Fulcrum would be either your dream keyboard or your nightmare keyboard. Not sure which

I humbly suggest the 40-key version of the Fulcrum, which will give your thumbs a multitude of ergonomic options

Reminds me of my own handwired keyboard, https://github.com/herpiko/unk

I used to type on a Vortex Core with Cherry Blue switches for two or three years but not in daily basic. Maybe I only spent around 20% of my typing time on that keyboard, the rest is on my laptop keyboard. The Vortex Core is still ok now and I love it. Then came time (last year) when I build my own handwired keyboard using Gateron Brown switches. Since then I spent up to 90% of the typing time on this handwired keyboard, until now. It has been a year. Now some switches became annoying: fail to register, double register and so on. General issues which I found on mechanical keyboard forums. I've done the thing that need to do: cleaning, blowing it with air duster, etc. The problem may be gone for one or two hour but then it keeps coming back.

Here is the build log: https://github.com/herpiko/unk