That passage says that the scripture is, of course, inspired and “profitable”; some translate that as “useful”. St. Paul did not say that the scripture is also sufficient. Indeed, the letter several times also mentions oral teaching, including in verse 14. In that context, it is clear that the scripture adds to other schooling, and this combination of tradition and scripture produces a fully equipped clergy.
Verses 16 and 17 plainly state that Scripture is adequate to be equipped for every good work, to be a Christian.
And note that 14 also states plainly that what Timothy had learned since childhood is all sufficient for salvation.
Anything added beyond the Scriptures may HELP you reach salvation, and can help you understand Scripture. But - per Scripture (verse 14-17)- it is not necessary. It is extra-Scriptural and not required for salvation.
I do not deny that many of the writings of the early church fathers, or even modern theologians are beneficial and wholesome to read! However, they add nothing more, and cannot offer any additional information required for salvation. The Scriptures are all-sufficient, per the Scriptures themselves.