You did not mention your office dress code.
If Business Formal (suit & tie), there is no casual shoe that would be appropriate. Period.
If Business Casual, check to see what the execs are wearing. Nice loafers in black or dark brown may be acceptable if they are the chino & polo set.
If Casual, then you are OK to proceed with you goal of dressing down for work, although I caution what message that sends to the management about you.
As far as colors: black is universally accepted, with dark brown as the 2nd pair. Cordovan could be considered for 3rd, followed by one of my favorites for a nicer casual look: dark navy.
From a practical standpoint, I recommend that you do NOT follow through with this plan. It will be hard to keep your shoes in the tip-top shape that should be expected of work shoes. And as mentioned above, you should rotate your shoes.
Also as mention, comfort has to do with fit, not with style or type of shoe.