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.
It’s very funny you say MOV and HEIC are proprietary and then list MP4 considering
Also Android can totally read at least HEIC images. Not sure about MOV. Any of this is also not related to the problem the OP has.