For other split-mechanical keyboards check out:
ZSA Voyager
Moergo Glove 80
For other split-mechanical keyboards check out:
ZSA Voyager
Moergo Glove 80
For keyboards really similar to OP's
The keyboard they were inspired by (not for sale... yet?): https://old.reddit.com/r/ErgoMechKeyboards/comments/1cfg3vr/...
Corneish (out of stock): https://lowprokb.ca/products/corne-ish-zen?variant=376943319... Unicorne: https://new.boardsource.xyz/products/unicorne-LP
The corneish is an absolute gem in my opinion. It is possibly (probably?) open-sourced too.
Ambients Silent Choc Switches (20g Linear), keycaps from worklouder (Pure)
Edit: nevermind, I just learned that the advantage360 pro uses ZMK as well. Either way, they both seem like great options for people who prioritize the ergonomics over aesthetics :)