Anyone have any suggestions on ergo boards or anything else (e.g. like that moonlander board in OPs post)
If you work for a FAANG, is there a company-provided ergonomics specialist available that you can consult? As the OP points out, the answer to your problem
may lie in your changing your work habits rather than messing about with various keyboards.
I ask because this part of your post:
I find I apply pressure on it when resting my wrists on my macbook.
...alarmed me somewhat. It has long been my understanding that resting your wrists on
anything whilst you are typing is ill-advised.
Any road, I am hoping your company has someone on-site who can take a close look at how you work and can give you good advice (rather than the sort of half-guess someone like me can furnish).
One thing I did want to clarify:
on my macbook.
Do you use any of the keyboards you mentioned you had purchased with your MacBook? I ask because I am convinced that the corollary to laptops becoming thinner and lighter is that laptop manufacturers no longer bother incorporating keyboards meant for any sort of serious, long-term typing into their products.
I spend a fair amount of time on a laptop myself, but I would not dream of using the built-in keyboard for anything more than keying in a few search terms now and again. The point being: I would think using any one of your newly-acquired keyboards would be better than continuing to use your MacBook's built-in keyboard for extended periods.