So if I make a beat on garage band using the loops there, would I be able to use it towards my own songs and publish them or would I have to create my own beats based on my own instruments?

The GarageBand licence allows you to use the GarageBand loops for your own commercial work, see here:

Using royalty-free loops in GarageBand with commercial work - Apple Support

The GarageBand software license agreement says:

"GarageBand Software. You may use the Apple and third party audio loop content (Audio Content), contained in or otherwise included with the Apple Software, on a royalty-free basis, to create your own original music compositions or audio projects. You may broadcast and/or distribute your own music compositions or audio projects that were created using the Audio Content, however, individual audio loops may not be commercially or otherwise distributed on a standalone basis, nor may they be repackaged in whole or in part as audio samples, sound effects or music beds."

So don't worry, you can make commercial music with GarageBand, you just can't distribute the loops as loops.