A more careful analysis: "C++" requires the use of the shift key for all characters, and extension below the home row and to the top row. On the other hand, the characters of "Go" are on the home row and the row above. The shift key is only required for the 1st character.

So the actions for typing "C++" are going to be [shift] [C] [+] [+]. For typing "Go" [shift] [G] [o]. The "+" keys are repeated, which makes the 2nd action faster. However, the spread between C and + is much wider than between G and O.

I would guess that it's probably 33% more.

You need three keys or two keys and a long hand movement to type C++, but you only need two keys for 'go' - and the keys for go are alternate hands and strong fingers, but even the nearest + symbol requires a weak finger or a contortion.

Also, go is typed as a typical word more often than ++ is, so it's more habitual and familiar and automatic.

I suggest it's much faster.