https://www.zotero.org/ 
zotero finds reseach papers automatically,
zotero now has in-buit pdf reader (see below vid) - very powerful - 
web addon is way fast than everyweb addon

qiqqa is good for searching - brainstorm -  but not user friendly at all.
endNote has to purchase .. ( free with some institutioal licences) - 
mendely not bad (they say they want us to use web addon - but that addon sucks )

try these also : 
https://www.webofscience.com/
https://www.connectedpapers.com/
https://musingsaboutlibrarianship.blogspot.com/2020/06/more-researchliterature-mapping-tools_16.html