Fingernail can scratch cooking board = too soft?
Since it's not all that clear what your question really is, I'm going to go with the question in the title:

If you can mark your dry cutting board with a fingernail, the wood is softer than you want for a good cutting board.  In fact, your cutting board would need to be a very soft pine, fir, or similar wood to be that soft, none of which are ideal for cutting boards.  This explains why you have "deep grooves".

I own a teak cutting board (it was a gift), and I don't know that I'd recommend it.  Teak is hard enough to dull my knives faster than a softer hardwood like beech or maple would (bamboo has the same issue).  Beyond that, there is quite a bit of debate about which wood is best for cutting boards and instead of trying to reproduce it here I'm going to give you some reading:


Tasty Kitchn's Best Wood for Cutting Boards
Serious Eats Recommendations on Cutting Boards
Brooklyn Butcher Block's opinion on various woods