不好意思又繼續發問了，
朋友找到了以下的資訊，覺得互相抵觸，
他滿焦慮的，所以再麻煩大家幫忙解答一下，謝謝！
他DS-2019會在5/1結束，下個program 7/15開始
https://tinyurl.com/tv4l5s8
他對這段有疑惑
What if I have a gap in status?
If your current nonimmigrant status will expire more than 30 days before your F-1 or M-1 program start date and you wish to remain in the United States until your start date, you must find a way to obtain status all the way up to the date that is 30 days before your program start date (“bridge the gap”).
(1)但我覺得這整個網頁不適用J-1 student，他們是在討論「非用於就學」的status？
(2)如果適用於他，就又回到可能要申請B2來填補gap的問題了？
https://tinyurl.com/whtc8ws
他對這段有疑惑
If you are an international exchange visitor (J-1), you may not change your nonimmigrant status if:
You are an exchange visitor and are required to meet the foreign residence requirement, unless you receive a waiver.
(2)他認為他有兩年條款221(e)，而且沒申請waive，所以不能COS？
https://tinyurl.com/uhp6ht2
他對第二段有疑惑
you may apply to change your nonimmigrant status if you were lawfully admitted to the United States in an eligible nonimmigrant status, your nonimmigrant status remains valid
(3)他想知道remains valid是指到核可前都要valid嗎？我覺得是file I-539時valid就好？
https://imgur.com/a/Xx4DXoZ
這間學校DSO直接說如果你的status在I-20 start date的30天前就結束，
COS will most likely be denied
(4)這是真的嗎？
(5)我個人是認為有試有機會，被deny就離開美國申請visa，但沒試就沒機會啦...
他怕很接近7/15時被deny，如果大使館早就回復簽證面試預約，
到7/15才離開美國申請visa反而會無法準時開始program，
如果COS不安全，倒不如不要。
跟我的想法完全相反，我是覺得離開美國以目前疫情狀況，未知數更多XD
發問多次，麻煩各位了，謝謝！