A bluetooth drop-in PCB for the _33 keyboard by tominabox1. Documentation is available here, and the ZMK config repository is available here.
The board can be produced at JLCPCB for rather cheap, and through their PCBA service they will assemble every component other than the the Holyiot 18010 module. You'll need to purchase this seperately, and solder it. Files for this can be found in the Production Files directory, when ordering make sure to choose "assemble bottom side" and tooling holes aded by JLCPCB.
You'll also need to flash the bootloader to the Holyiot module. The bootloader file can be found here, and should be flashed using an ST-Link V2 clone, or a J-Link. Details for how to do this are available on the nice!keyboards wiki, and on the nRFMicro wiki. Please note that the Holyiot module does not need to be unlocked.
Alternatively, you can choose to export files suited for another manufacturer, such as Elecrow or PCBWay, where they will assemble the entire board. Some manufacturers may also be able to flash the bootloader in their factory, so this may be worth asking your customer support representative.
Thank you to Makenova and Matthew Dias for funding the open-sourcing of this project.