Android, Apple, RCS/SMS/MMS, Two Apple Accounts, Seems Completely Random? Any Help Appreciated!?!

Hello everyone, I am aware that there are quite a lot of post out here right now regarding iPhones iMessage settings and/or Contact info being pulled together by the iPhone itself, which has been doing weird messaging, email or iMessage issues. However, I've not quite been able to find any post that really is more focused on, much less any usable information or solutions that have done anything whatsoever.

First, I actually have and Android and that is on a separate network then my friends iPhone 14 Pro Max. I ALSO have an older iPhone that I used for gaming ect... and would use it from time to time using iMessage to talk with my friend. So when we first met, I'd use my Android to RCS/SMS/MMS text them, and using the iPhone iMessage to message back and forth. At this time, both conversations were separated on her iPhone 14 Pro Max, and additionally even when using iMessage I would not get any kind of emails sent to my associated Apple account email related to any messages.

It's been 6 months or better now, where I haven't even used the older iPhone or iMessage at all, but when messaging her through RCS or even switches sometimes to SMS/MMS text, I will get what seems so random email that I do have an Apple account with, from her that looks like this, her (phone number)@mms.att.net and it will be sending to both, (Apple email)@gmail.com and also my (phone number)@mms.att.net. I do not even have service through AT&T, and we have completely deleted my contact and just add the phone number, but it will still happen. Sometime it can actually just go days before even starting back up, and will send the next 50 of her messages to both my email and phone number.

I really am not positive if maybe she's turning something on or off, if it is Wi-Fi related or not, since a lot of the time its usually while she would be at work where there is poor connection. The things I do know, is when I do get the emails, it has always said the @mms.att.net. It always says, for some reason since I do get the RCS/SMS/MMS text on my phone but it sends it to my number@mms.att.net even not being with them. She has said it may have something to do with her replying on her watch. I probably over explained to a point of confusion, but any help would be really appreciated, and if any more information would help that I could get, just let me know. Thank you.