You started off using evidence from your own game, but after I questioned your logic you started talking about the pros instead. I'll take this to mean you're conceding the point from my last post (see my last post).
Those are very selective comparisons.
Safin and Nalbandian are on the short list of all-time great 2hbh. Whereas Federer should not
be on the same list for 1hbhs, certainly not for power. And Gasquet's bh is overrated. He can make an occasional highlight reel, but based on his normal exchanges I don't think he should be on the GOAT list.
Both Federer and Gasquet tend to hit spinny balls. For consistent power I prefer both Almagro and Wawrinka's bhs.
As for Marat Safin, he was a big, powerful guy (6'4" and strong). He should
be able to crush the ball with a 2hbh from his physique alone.
As for Nalbandian, while he isn't tall, keep in mind he does have very broad shoulders. I think one of the things that makes his bh great isn't just pace, but rather his ability to hit consistently deep.
Here's his GOAT-contender 2hbh against a good 1hbh of another mature player (Haas). I don't think it's clear that Nalby's hitting much faster than Haas. And if he is, it's because Haas doesn't hit as hard as Wawrinka (sadly, I can't find good-quality videos of Nalb v. Waw).
Since you've mentioned a big, strong player (Safin), I'll go the other way and mention a tiny one: Justine Henin. She was generating at least as much power as her rivals on the bh wing, yet she was much smaller and lighter than any of them. There's no way should could have generated more power using a 2hbh.