they cannot be compared as they are not in the same league. TMC in my opinion is just a money grabbing exho. It has no value otherwise would have been included into the so called Golden Slam. For me Olympics gold medal is of no importance either but is in the Golden Slam so ...
The term "Golden Slam" was created to label what Steffi Graf accomplished in 1988 (when Tennis was just new as a full medal sport at the Olympics).
Had somebody won the 4 Slams + WTF any time earlier - which isn't the case(!) - maybe the label "Golden Slam" would have been occupied already.
Okay, the Olympics format indeed is much closer to the Slams, of course, but whether that's the reason for the naming is not this clear.
As far as I know the very term "Grand Slam" (for 4 Slams) wasn't even there or at least not important before Laver won it.
So, maybe in the future, when somebody wins 4 Slams + WTF, we will learn about a "Diamond Slam
" or whatever.