Issues configuring Kibana Watcher SMTP Server

Like the ones before me, I've been running in circles for the last few days haha.
When I modify the user settings with my SMTP server (SendGrid) in the elastic.yml file, I get a "this changes are not allowed".
I don't know if my settings are wrong or that feature is deprecated.
I've followed all the available documentation but nothing. (xpack-watcher.actions, etc).

I also found this related topic:

My question is if the automatic monitoring email service via SMTP is deprecated? or maybe my elastic cloud deployment is not compatible (v7.13.3) ?

Thanks in advance!

Can you give me the exact setting name you're trying to set in Cloud? If I know the setting I can try to figure out what's going on.

Best,
Oleg