Migrated Wordprrss website domain,e mail and SMPT .....

Please read all of the below.
Do not reply to this message if you don't have all the pre-requisite skills and knowledge.
I need task to be completed today.

Wordpresss site has been moved from Azure to Siteground. Domain is still pointing at old site.
Email is Outlook365.
I need the domain settings to be checked to ensure they are correct and if not you will need to advise what they should be.
I need the email domain settings to be checked
I need the SMTP functionality setting up so that the submitted forms get through to the company email - currently errors
I need someone to tweak the settings so the main image loads quicky, it's a small WEBP but when the site loads up it's the last thing to load.
The last person on this site who replied was way out of his depth so I want someone who doesn't have to google the answers.

You will have access to everything except the domain so I will provide an excel with the current settings and a screenshot and I will make the edits.

If you have any questions please ask.