Messages sending from iCloud or as RCS instead of being sent from my number

I recently came back from vacation and turned on my esim/line with AT&T as soon as I landed. My previous messages that were sent to me during vacation notified me after turning on my line. A day later, my messages were being sent through as RCS messages and I found out that I could make calls and send blue SMS messages to certain contacts. Other contacts, specifically group chats and my mom or grandma, would receive my messages, but I wouldn't receive their replies. I contacted AT&T and, after speaking with three representatives, they resolved this issue. They had me restart my phone, turn my line off and on, toggle the iMessages on and off, and even disconnect my MacBook from my phone number. Another issue while being helped was that either my iCloud or number would be checked under Send & Receive in iMessage settings instead of both things being checked off like normal. My problem was solved until the next day, and my same problem came up again. How would I fix this permanently and prevent it from happening again in the future after flying out of the country?