It's been a while! Sorry about the lack of updates, especially when it comes to batch 2.
I'm finishing my last year of engineering school, and I had even less free time than I thought. This summer, I'm hoping to launch batch 2, with a focus on improvements on the build experience and maybe some case upgrades.
Summer is a long way off I know! but if you're eager to build your own 4c the files are on GitHub if you want JLCPCB or someone else to manufacture it for you.
In the meantime, I do have a beta update for 4c owners, upgrading ZMK to zephyr 3.5, including an experimental BT mode (enabled by default)
Try syncing your forks with this branch if you want to test it out! Many other zmk boards have seen improvements to Mac connectivity with this upgrade.