I believe that the issue is that Android cannot use iMessage, and the result is that images / videos are compressed by SMS.
Don't know if it's an actual fix, but it is a workaround. If your iPhone friends send you iCloud Link with the photos / videos.
Another option is if both you & your friends are using WhatsApp, Facebook Messenger (Neither of which I would ever use), or Signal Private Messaging. These 3rd party apps will leave the original quality sent from an iPhone, relatively untouched.
On samsung, you can also send the media files via quick share. Instead of sending the files directly, you can have it uploaded on to the Samsung cloud and send the link for them to download. You can also set an expiry date so that the media files are deleted automatically after a few days so that it doesn't stay forever in the cloud.
