Try this site Irwin.... https://www.fiverr.com/categories/music-audio
They have songwriters, beat makers, instrument people, producers, singers, you can get some very cheaply too, like 5 dollars
Ask somebody to make you a very basic piano or guitar, bass track, in your style hip hop, R&B. Tell them what you would like it to sound like, or be similar to. You can then take that, and put your own beats over it, or write your own lyric or melody, you can find a singer.
For you, i think youd be better off with a basic keyboard, bass, track, and you can add your own parts to it.
Go to session musicians section, and check off hip hop and R&B, and you will see all the available people
Maybe you pay 10 , 15 dollars for a starter track, and you will own all the rights to everything you get from them.https://www.fiverr.com/categories/music-audio/session-musicians?source=gallery-listing