Good works vs First Love

Nevertheless I have this against you, that you have left your first love.  Remember therefore from where you have fallen; repent and do the first works, or else I will come to you quickly and remove your lampstand from its place—unless you repent.
Revelation 2:4‭-‬5 NKJV

Jesus said to him, “ ‘You shall love the Lord your God with all your heart, with all your soul, and with all your mind.’  This is the first and great commandment.  And the second is like it: ‘You shall love your neighbor as yourself.’  On these two commandments hang all the Law and the Prophets.”
Matthew 22:37‭-‬40 NKJV

"Throughout the NT love for God / Christ is emphasized (Rom 8:28, 1 Cor 2:9, 8:3, Eph 6:24) as is love for our fellow believers (John 13:24, 15:12, 1 Thess 4:9, 1 Pet 1:22; 1 John 3:11, 14). Indeed, the one demands the other, for one cannot love God without loving his children and vice versa (1 John 2:9-10; 4:16, 20-21). In a striking parallel to this passage, love in 1 John was a test for orthodoxy (see 2:7-17; 3:10-24; 4:7-5:3). It is clear that the Ephesians loved truth more than they loved God or one another. This does not mean that they were not believers or that they had no love at all, for the commendations of verses 2-3 would be impossible in that case. Rather, their early love had grown cold and been replaced with a harsh zeal for orthodoxy."

"These are not just "good works" but "acts of love" toward God and one another that characterized that early years of their church. Their battle against heretics could certainly be construed as "good works", but because it was not accompanied by love (see 1 Cor 13:1-2), it was insufficient. In short, orthodoxy without orthopraxy is a false religion."

- Grant R Osborne, Baker's exegetical commentary on the New Testament for Revelations, page 116, 117 on the Letters to the 7 Churches of Asia Minor.

Therefore the term "good works", is not restricted to mercy works only, but includes our services to God in the church, towards one another, which in the case of the Ephesians, is defense against heresy. The failure of the Ephesians at that time, is when they had done all these not out of the Love that the first Generation Ephesian believers did in Acts 19.

Hence returning to first love, does not merely mean going back to good deeds (which the Ephesians already did), but to do it with love.