Yuyumamoru I don't know what you mean when searching using tags all you are given are popular and new look here for an example https://www.webnovel.com/tag/list?tagId=41000016&tagName=System&type=1
and the popular option sucks it only list novels webnovel makes money off of
For instance Chrysalis as of March 24 2020 is 32 overall and 9 in original when It comes to the ranking for works on webnovel yet when looking for works under system tag it's listed as number 81 in popularity for system webnovels.