Cannot disable MMS link sharing without creating Samsung account

When I try to send a picture using the standard SMS/MMS app "Messages", my Samsung S20 does NOT send it as an MMS. Instead, it sends a plain SMS with a web link to a deep subdomain of 3gppnetwork.org (for example https://ftcontentserver.rcs.mnc001.mcc288.pub.3gppnetwork.org/cs/...etc . ). I found these Samsung instructions on how to disable this "feature". But when I click on the "Off" icon to disable link sharing, I come to screen offering "Connect to your Samsung account" or "Continue with Google", and no other option to continue. So how can I disable this without creating a Samsung account or giving Samsung access to a Google account, which should all be completely irrelevant to sending MMS messages.