Comment by immibis

In most cases filters based on the "from" address are enough. Sometimes the subject is also needed.

Unsubscribe from marketing emails you don't care about. The USA, surprisingly, has a law where if they don't have an unsubscribe link at the bottom, the CEO of that company goes to jail. I presume this law only passed because politicians got annoyed by spam. Use it.

Sometimes you do want them but want them to be out of sight (e.g. emails from digi-key about new products). Then filter them.

You can use email aliases if you want to. If you have your own domain you can use any address you like and even if they're not separate mailboxes you can use the "to" address for filtering. Gmail provides unlimited free aliases: yourname+anything@gmail.com is an alias for yourname@gmail.com and so is y.ou.r.n.ame@gmail.com (for sites that are aware of the + aliases).