Modern tech means if you send an apology text and leave it at that the rest is what it is.
Even if he choses to not read it for some reason that is not on you, you did your part.
If he reads it and ignores it the same.
I half agree/disagree with the no need to apologize out of your way.
If you lived in this new city and it was the 1700s i would agree. If you borrowed a quarter and forgot to give it back I would agree etc.
To send a text is of nothing from you and he may never even respond or simply send a “whatever” so be it. You are done with it and conscience served.
Also he may half ignore it but someday he may see it as a show of what a person who does wrong can do. Perhaps it will have an impact on his outlook, his actions to someone he wrongs…
Just send a short clear and sincere text and be done with it. If he engages negatively leave it be do not give in to reigniting animosity etc.
Tis simple