Trademark

Copyright protects the video you made. A trademark protects the name you make it under, along with the logo and any slogan, and it exists so customers are not misled about who they are buying from. Registration is per country and per class of goods, so a mark covering clothing does not cover software, and a UK registration does nothing in the US. Creators usually meet this from one of two directions: launching merch and discovering the channel name is already taken in that class, or receiving a complaint for putting a company's logo in a thumbnail. Rights also build up through use in the UK, though enforcing an unregistered mark is slower and dearer than pointing at a certificate.