import re
text = '''string=""\n( 2021-07-10 01:24:55 PM GMT )TEST  \n---  \nBadminton is a racquet sport played using racquets to hit a shuttlecock across\na net. Although it may be played with larger teams, the most common forms of\nthe game are "singles" (with one player per side) and "doubles" (with two\nplayers per side).  \n  \n  \n\n  \n\n( 2021-07-10 01:27:55 PM GMT )PATRICKWARR  \n---  \nGood morning, I am doing well. And you?  \n  \n  \n\n  \n  \n  \n---  \n  \n  \n  \n  \n---  \n  \n* * *""'''
left_rx = r"\(\s*\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}\s*[AP]M\s+GMT\s*\)\w+\s*\n"
rx = re.compile(fr"^{left_rx}---\s*\n(.*(?:\n(?!(?:{left_rx})?---).*)*)", re.M)
print ( [x.strip().replace('\n', ' ') for x in rx.findall(text)] )

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