Eh, as you mentioned you “never had a sim card”Could you explain more detail about this?
I asked because  Koodo service need an active sim to work. As of now, are you a current Koodo customer?

Sorry. My mistake. I meant to say SD card. Not that should have anything to do with the MMS issue.

Is it only MMs capability lost ?

Can you send/receive text? And your data working?

Only MMS capability. Everything else is fine.

Could you check your APN settings to see if it was set correctly as per this https://www.koodomobile.com/en/help/setting-data-your-non-koodo-phone

Also, was RCS was on in your device?  https://www.koodomobile.com/en/help/next-generation-messaging

I checked everything. All was good except the APN type was listed as "Default, supl, MMS, dul". I eliminated "dul" and I changed my default messaging app to Google messages. I can send MMS now. Problem solved.

Thanks for your help. Appreciated!