You researched the person. Therefore, you are in a better position to merge the profiles because you know all the relevant information about the person assuming you didn't just blindly accept hints on Ancestry or FamilySearch.
Both biographies are a mess due to not being edited after a GEDCOM import. Use this browser extension to clean up the profiles
https://www.wikitree.com/wiki/Space:WikiTree_AGC
Once you clean up the profiles begin the merge and have both biographies selected. Manually delete duplicate information and manually select what information to keep from both.