Questions to maybe consider:
* If you're relatively new, are they giving you starter tasks?
* Are the other team member's tasks harder, less-straightforward, involving less-familiar tech, slowed/blocked by dependencies, less amenable to just crunching through mechanically, etc.?
* Are the other team members doing higher-quality work? (A big corp. might have very different ideas of what software engineering is than you did in a one-person-tech-team startups. Are you a one-person tech debt machine?)
* Do the other team members have more responsibilities separate from this code?
* Is the team in a catch-your-breath period, after a big push to ship something, and people also taking summer vacations, etc.?
* Is there a morale problem going on that you haven't picked up on? Were there layoffs recently? Or do people know something you don't know, like that the project is going to be canceled? Is this a team or company that people want to be in? Is everyone interviewing or practicing Leetcode?
* Why is the tech lead or people manager not on top of this, if it's a problem? (Or maybe they are, but they're handling it discreetly, one-on-one with people, rather than embarrassing people in front of the team?)
These questions also suggest one way to broach the topic with a tech lead or people manager, if you don't yet know whether it's safe to speak more candidly: you could ask how your work is fitting the conventions of the organization, are you blowing through tasks too quickly, is there something you should be doing differently, etc.