I got MMS restored on my OnePlus 11 following the APN settings from here: https://productioncommunity.publicmobile.ca/t5/Get-Support/Re-OnePlus-11-5G-MMS-messages/m-p/1155783/highlight/true#M806354
Thank you very much for the reminder. I just filed a complaint with CCTS and am waiting for them to review my complaint. My OnePlus 11 is barely a year old and I did not receive any notice in advance.