I like the wood spacer. What did you use for that?
You can find a PCB design and order it from a manufacturer (typically a 5 unit minimum). There are likely thousands of open source designs out there.
I’ve enjoyed putting together kits from Boardsource, Little Keyboard and MechWild. These kits all start with the PCBs and components and you solder it all together, and you can usually order hotswap or solderable switches in the same order. You’ll have to flash the MCU too. Most of these are split ergos, which I like, but not a lot of them are 75%. You’ll have to do some looking around.
Split spacebar, typically one is an enter key. Not sure what the middle would be used for.
Eh the software handled all that. Rounded corners tho… <shudder>