Song was always part of Church worship, and Paul even includes snatches of hymns in his letters. The first “assemblies” were small gatherings, modeled we can assume after Jewish synagogue services, including at least sometimes, a celebration of the Last Supper.
I am all for singing and for communion. But they are not in and of themselves worship unless the worshipper has the right heart attitude and true faith as outlined in God’s Word. If you worship with a wrong attitude or worship a false god made in the image of your own choosing rather than the one revealed in scripture then it may be a kind of worship, but it is sin — even if you sing like an angel and have the most elaborately beautiful service.