The outsized impact of a bad employee is definitely a potential of a small team / company. Maybe I've just been lucky, but for the most part the closeness of a small team also invites more visibility and accountability from owners. Bad managers and employees, in my experience, tend to have shorter careers in small companies.
On the other hand, I've seen "staff" engineers at large companies who clearly have "leaves feedback on PRs" as a performance metric, because they would add trite, useless requests for changes that would conflict with feedback they left on other PRs, and would be exceptionally petty when confronted. These same people would be lauded because they lived up to artificial expectations, despite probably having a negative impact on the teams ability to deliver if anyone really looked at what they were doing.
On a small team, you can't get away with that for very long before it becomes apparent that something isn't working.