There are also https://baike.so.com/ , https://www.baike.com/ and probably some others I don't know about. I don't think the authorities care which one people use so long as it complies with "relevant laws and regulations" (i.e. censors content). There doesn't seem to be much user loyalty either; people use whatever their search engine puts first, so baike.baidu.com if you search with Baidu and baike.so.com if you search with so.com.