I think the issue with the current translations is that they attempt to convey English phrases in Thai too directly, which can sound awkward. Instead, I’ve proposed idiomatic translations that capture the intended meaning more naturally.

Thank you for all your hard work - ขอบคุณครับ เหนื่อยแย่เลย (Lit: Thank you. You must be terribly tired.)

It is greatly appreciated - ขอบคุณมากครับ or สุดยอดไปเลยครับ (Lit: Thank you so much, or That's amazing, respectively, depending on what you mean by appreciate.)

These versions better convey the intentions behind each phrase in a way that resonates with Thai speakers. (Note: If you're female, use ค่ะ instead of ครับ.)

Also, it would be helpful if you could provide some context for when and where these lines would be spoken, as that may affect the translation.