SMS Group Support
It's inevitable that someone in a group of friends does not have an Apple device. There are also some who do not have an iPhone, but still have an Apple ID.
This causes a nightmare when trying to text a group. Apple states that SMS is a feature of the carrier, which is partially true. You could say the same about calling someone. The software we use to interact with carrier features (like phone calling and SMS), is entirely up to the phone manufacturer.
That being said, when will you either update the software to better handle SMS groups (as all other phones have done) or when will you stop punting this issue to the carriers and simply state that you're not interested in supporting this feature.
I've beat my head against the wall trying to manage a text group on an iPhone with SMS participants. It's super simple with my Android and impossible with my iPhone. Additionally, when I switched from iPhone to Android as a primary phone, it took months for my wife's texts to finally stop using iMessage. It worked fine for years after deregistering my phone number. However, we recently added an iPad to my Apple ID account and guess what? No more text messages from my wife. They were going to my Apple ID again even though the iPad is not associated with ANY number and my Apple ID has no record of my phone number.
It wasn't until I deleted my email from my wife's phone that her phone finally began to send SMS to me again. I even tried to disable iMessage, but the phone was forcing her to use iMessage, which I suspect is a way to monitor data.
iPhone 11, iOS 15