As an American English speaker who is currently learning German, I definitely do NOT agree that German is the easiest language for English speakers to learn.

I learned Spanish as my second language and speak it fluently, and I speak passable Italian. I even picked up enough (Brazilian) Portuguese to get by thanks to my experience with Spanish and Italian (although spoken Portuguese is harder for me to understand). All three were definitely easier than German. I'm sure that has a lot to do with the fact that I first began learning Spanish when I was 11 and Italian at 15. But still, German grammar is definitely trickier to me.

Regarding this:

Especially if you come from a country that usually has a massive accent - like America.

It's true that a lot of American English speakers have trouble getting rid of their accent, but it's by no means impossible. I'm not claiming my Spanish is 100% perfect (I still occasionally make a minor mistakes here and there when I'm speaking), but I definitely got rid of my American accent. When I'm in a Spanish speaking country, people generally ask if I'm from Italy or Brazil. I'm usually told that I just sound vaguely foreign. That probably has a lot to do with learning Spanish pronunciation at a young age.

All that being said, I hear people speak English with very strong accents from their native languages all the time, and I understand them just fine. I've worked with people from France, Sweden, Denmark, Chile, Russia, Mexico, China, Taiwan, India, Pakistan, and other countries. All with accents ranging from very light to very very strong. My ability to work with them is not hindered by their accents. For context, I work in software development.

The only reason I mention this b/c I don't want someone to stumble on this thread and think to themselves "Oh god, I'm never going to learn a language perfectly, and I'm definitely never going to get rid of my accent!", get discouraged, and give up.

a) It's possible for an American English speaker to get rid of your accent (or at least diminish it a lot). b) even if you can't get rid of your accent, it's still worth learning another language.