No.

If other people’s photos are only in Moments and there are no similar works on Douyin, your original work will not be affected if you post them to Douyin.

The main reason for Douyin's non-original assessment is transfer. Douyin strictly prohibits transfer. If you often transfer other people's videos, you may receive an official notification message from Douyin. The message will tell you that the rating has been lowered due to excessive content being moved.