Do I need a Business Manager?

No, you don't need to create a Business Manager, but most assets on Facebook are owned or managed through one.

We work with Facebook Pages and Instagram Professional accounts, whether they're connected to a BM or not. You'll see everything you're authorized to use during the linking process.

TikTok and YouTube don't involve a Business Manager at all. TikTok links through your TikTok login, and YouTube through the Google Account that owns the channel.