Not yet all things.
It's a process, obviously.
not yet
The Lord Jesus Christ isn't doing any reigning now. He is waiting at God the Father's right hand, like the verses quoted says: UNTIL. Now, once He has accessed His own throne, He will rule.
"But
when all things shall have been brought into subjection to him, then the Son also himself shall be placed in subjection to him who put all things in subjection to him".
Thus,now not all things are subjected to him, otherwise the Son would have given up the kingdom....
1 Cor 15:25 KJV doesn't say that He is reigning now. Verse 25 is about after His coming, as verse 23 shows.
He will reign after His coming. That is not yet.
Ps 110 is quoted in Heb 10.... "He sat down in perpetuity at the right hand of God, waiting from henceforth until his enemies be set for the footstool of his feet." So, the Lord Jesus Christ is now waiting,
UNTIL.
In Heb 2:8 KJV, it doesn't say "has put all in subjection", but "For in the subjecting all things to him", which is an explanatory statement of the subjection he talked about 2:8.. It says how it is to be understood: nothing
will be left "unsubjected" to Him. God the Father does the subjecting to Him, while He is waiting at His right side, on God the Father's throne. We do not see it yet-it will be realized in the future,and manifested to all, who will see it, as He appears in glory appear in glory. Then all will see it, even those who have pierced Him.
Hebrews-The only Begotten Son is seated at the right hand of God. We see the Lord Jesus Christ as man, (he was made a little inferior than angels) crowned with glory and honour. But we don't see yet all things subjected to Him.
"not yet"
The "He must reign until all enemies are under His feet," which are 2 different subjects/things, is when the Lord Jesus Christ reigns. Then "the man of war" puts the enemies under His own feet, with the last enemy being death. After which He gives up the kingdom to Gof the Father. This is different, from the period in which we are today, where God the Father is subjecting the things under the feet of His only begotten Son.