Edit: NOTE, I am the receiver of the texts.
So many people asking me to have my wife do something different on her end.
Beloved, she is on iPhone because she doesn’t want to do anything “weird.” She is texting from her phone number using her texting app. That’s what’s going to happen.
Now, why can’t I get iMessage on my android phone? If it’s just a messenger app why not make it available for Android?
I’d use it.
Unless I did a really poor job researching it, you cannot change your default SMS/MMS application on an iPhone.
You can use other messaging apps like Signal, Whatsapp, Telegram, or AIM. But if you want to use SMS, you have to use iMessage.
Maybe this is US-specific though. Europe often forces Apple to do things they don’t do here.