Even if I go back to Japan, I'd like to be able to do this job by myself.
If I were to return to Japan now, I'd like to pursue this job on my own.
ーEven if I go back to Japan, I'd like to be able to do this job by myself.
「日本に戻ったとしても、この仕事を一人でできるようになりたい」
to go back to ... で「…に戻る・帰る」
to do this job by oneself で「一人でこの仕事をする」
ーIf I were to return to Japan now, I'd like to pursue this job on my own.
「もし今日本に帰るなら、一人でこの仕事を続けたい」
to return to ... で「…に帰る・戻る」
to pursue this job on one's own で「一人でこの仕事を続ける・従事する」
ご参考まで!