Individual Contribution Vs Team Contribution

How does it work for your teammates? When they talk about tasks where they did 95%+ of the work, do they use "We" or "I"? If they use "We", I think it's a fair piece of feedback to maintain the collaborative aura of the team. It's admittedly a bit weird, but I get it. If they use "I", then your teammate is being hypocritical and that is strange.

There might be something deeper here where you'll need to read between the lines a little bit. It's possible this teammate is insinuating that you aren't recognizing them or other teammates who helped you on certain tasks, i.e. you are forgetting the help you received from them.

I would do some introspection here and try to figure out what's going on as objectively as possible. These communication things may seem small, but they do add up over time to meaningfully affect the team's culture and vibe.

If that is the case, why do we have individual performance reviews?

In a good team, almost everything will be a team effort as it's pretty rare for a task/project to be 100% silo-ed to just 1 person (this was the case at Meta and Robinhood for me). However, managers understand that different engineers will contribute different levels of impact to a project, particularly based on their seniority. This means that credit is usually divided and split for each project. I talk about this more here: https://www.jointaro.com/course/nail-your-promotion-as-a-software-engineer/depth-of-contribution/