AhsanAllahu ilaykum ustadh. We have a red jersey that we wear over our shirt that is partially see through and has no sleeves. Is it permissible to wear a red garment like this as long as our other clothes aren’t completely red?

There are different opinions regarding wearing pure red, whether it is forbidden or frowned upon. Bare arms are not ʿawrah for a man and the shirt underneath covers you, so the only thing left is that in ṣalāh something should be on your shoulder.