https://www.animelyrics.com/anime/ku...trightaway.htm

"I know I worked hard more than anyone else"

This should be changed to: I know you work harder than anyone else.

Here's why I believe the original is a mistake. The lyric in Japanese is "誰より努力してる姿". The word 姿 (sugata) makes it clear that the speaker isn't talking about himself. 姿 (sugata) is often used to refer to someone's silhouette or complete bodily form as viewed by another person. Literally the lyric is more like "A shape/form working harder than anybody". There's no pronoun specified, however the context of the lyrics before this one make it clear either "they" or "you" would be accurate. I think "you" is most likely correct because it's a little easier to assume that the speaker feels outclassed by one particular rival than multiple people here and "you" fits with earlier parts of the translation, where "you" was used.

There's no reason that the verb should be translated into the past tense here. 努力してる (doryoku shiteru) The way it's conjugated in Japanese indicates an ongoing state. The person the speaker is talking to/about has not stopped working hard. They're still continuing to work hard like they have been.

The word "more" isn't as big of an issue, but I think it should be removed because it's redundant now and possibly could make the meaning of the lyric less clear than it should be. With the "more" there, it's possible to interpret the meaning as the speaker knows how hard the other person is working more than anyone else knows that. Like he alone has this depth of understanding or privileged information. I think that's unlikely as the speaker is torn up inside about how much better this other person is doing to the point that he's been actively pretending not to notice and making excuses about it that he's now owning up to. Someone who works that hard at something likely has at least a few people who recognize how hard they're working.

The user who did the original translation doesn't appear to have been online in several years, so I can't contact them about this.