Yes, all verses on a given subject must harmonize.
As you correctly pointed out, Acts 22:16 says our sins are forgiven by washing in water. But what about these verses?
Eph 1:7,
In whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace;
Col 1:14,
In whom we have redemption through his blood, [even] the forgiveness of sins:
Rev 1:5,
And from Jesus Christ, [who is] the faithful witness, [and] the first begotten of the dead, and the prince of the kings of the earth. Unto him that loved us, and washed us from our sins in his own blood,
Both Paul and John say blood whereas Luke says water. What do we do with that?
I solve the problem by acknowledging that Acts is a transition book as well realizing that, while everything in the scriptures actually happened, not all those happenings were necessarily what God wanted.
What's your solution?
God bless.