Sending an SMS using Automator in Big Sur, new syntax?

Hi everyone!

I am a secretary for a community in my neighborhood and I often would use the Automator app to send out text messages to the members in my community.

In Big Sur things look to have changed a bit with the Automator app and the old syntax is no longer working. Initially I was getting:

"Messages got an error: Invalid key form."

using the following script

on run {input, parameters}

tell application "Messages"

send "test" to participant "1234567890" of account "SMS"

end tell

end run

The old syntax was using buddy and it wasn't "account" in that last section, it was service.

If I put the "SMS" field in the next line then the first error goes away but it's followed by an error that says that it "Can't get participant "1234567890" of account."

Any thoughts on this? Is sending text messages using Automator on Big Sur still a thing? It was very helpful in my job position to schedule automated texts but I can't figure out what I'm doing wrong.