In a compond sentence, two independent clauses can be handled in all of the following ways except that the two independent clauses are

a. joined by a comma
b. joined by a semicolon
c. separated in to their own sentences
d. joined by a comma and a coordinating conjuction

there is 2 main differences, basically which are the users and the market. the other difference is the kind of content

people who use tik tok are mainly people from east asia, kind of like the app douyin. musically, on the other hand, are used by people from america or european countries.

while tik tok videos show things like daily life videos, comedy, or just funny videos, musically are like people mimicking songs with their own actions, 'imitate' singers and video clips.

hope this !