Activity is the signal. Self taught but goes to a ton of meetups. Enrolled in one of the legit online master's programs, etc. Ofttimes bootcamps can appear on these resumes. Someone did a bootcamp, realized it wasn't enough and kept growing in a manner.

People who treat the bootcamp as the terminal level of knowledge plateau.

Not the person you are asking, but I'd say a genuine interest in the field.

A couple of simple hobby projects and participation in meetups and chats can give both faster ramp-up (beyond very basic) and solid job leads. My 2c.