How can I upload guitar/bass covers without getting copyright strikes?

From what I understand I need to get a mechanical license from a distributor like Distrokid but when I went to their website it says that I can only upload covers if I don’t use any of the original audio of the song. My question is how come so many big YouTube channels use the original vocals/drums/etc. of the song? I’m sorry if this is a stupid question but I couldn’t find any further information on the topic.