>However, in his another poem, Roll the Dice, he presents something entirely different outlook on the subject of trying.

Is it a different outlook? I think the "don't try" in the gravestone you mention refers to the same concept, or as Yoda put it "Do or Do not. Do not try".

"Don't try" to me reads not like "Don't do anything daring" (avoid trying stuff) but instead "Do things fully, don't just dip your toes in" (commit to stuff, don't do half-hearted tries).

Besides we do know that he did go all the way, he quit his main non-writing job (at a later age) and went all-in in writing.