a burden is
だんだん荷が重くなってきた。
It’s gradually becoming more than I can handle.
あの利己主義者では荷が重い
That egotist can't handle the responsibility.
— オッペンハイマー (2023)
この仕事、私には荷が重いよ。
This job is more than I can handle.
誰でも自分の荷が一番重いと思う。
Everyone thinks their own burden is the heaviest.