[yeahboats]

Have you looked into the various builds on r/ergomechkeyboards? A lot of custom layouts/pcbs, most all with hotswap switches and running QMK, which should let you keep your custom keys on device and not needing any software at runtime. (You'll have to program the firmware at some point though.) I went with one that had a build service as I didn't feel comfortable soldering just yet. Only downside is that cases can be a little unrefined and it's easy to get expensive quickly as they are more niche builds.

[kkfx]

Yes, but all share a common pattern: they try to be as small as possible. My personal vision is that OEMs have well sold "small is better" to spare materials and sell them at a higher price...

I'm living in Emacs (EXWM), with a binding strategy of a bind a single key hit or a mod+key because even with more spatial movement I'm still quick and with less mental context switch/overhead to move in space vs using "more mods"/keyboard layers or key chords...

In the past SUN Type 6 alike keyboards suffice, nowadays it's hard to find anything and start my own design demand simply too much time and effort to achieve daily usage quality for my tastes. That's about me of course, but the rant is in general: in the past some companies, even journals,have asked for custom keyboards to be more efficient, now the focus is just on consuming devices instead of producing ones. That's alarming IMVHO and worth to debate beside the rant...

[dendriti]

There are tools such as VIA which handle firmware for you, so you can just change a key in the GUI.