Yeah , it's a fairly significant project but very worth it in my opinion, that said Sofle(s) and Corne(s) can be found frequently for sale in the IMKC Discord
Also I can't vouch for CableSutra since I haven't used them personally
Nuphy makes some good quality low profile boards, or if you need something more ergonomic , you could try a Sofle or a Corne style board with Choc Switches