I wonder if similar split "kinesis" style keyboards exist with an extreme tent. I'm happiest when I'm typing with my hands almost in "handshake" position. Currently using an ErgoDoz EZ with books propping it up.
You may be interested in the ZSA moonlander with their "the platform" tent kit. It can go near vertical, got mine a few weeks ago and it is really nice.
Project description: The Ergo S-1 is a fully wireless, split ergonomic keyboard that is compatible with cherry/gateron switches and cherry/oem/dcs keycaps. It runs on the fantastic ZMK firmware.
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I made one of these a few months ago, and I'm a big fan. It's like an open-source Kinesis Advantage 360.