The difference, by the numbers
Both have lemon juice. Only the Earl Grey MarTEAni has simple syrup, gin and egg white; only the Ve.N.To has grappa, honey syrup and chamomile cordial. In parts, an Earl Grey MarTEAni is 1 lemon, 1¼ syrup and 2 gin; a Ve.N.To is 3 grappa, 1½ lemon, 1 honey and 1 chamomile. By volume, the Earl Grey MarTEAni is 46% spirit, 31% syrup and sugar and 23% citrus; the Ve.N.To is 46% spirit, 31% syrup and sugar and 23% citrus. That makes them close cousins on the ratio map.
The Ve.N.To is the stronger drink in the glass (11.5% ABV against 9.6%), but being smaller it holds about the same alcohol (1.01 standard drinks each). The Earl Grey MarTEAni has more calories (about 192 against 167) and more sugar (19.2 g against 16.1 g). Both are shaken; the Earl Grey MarTEAni is served in a martini glass, the Ve.N.To in a rocks glass.