Secure a MS O365 Exchange mail server

We are looking for a MS Office 365 Exchange and DNS specialist who are able to help us to secure our MS O365 mail server and get a higher score via internet.nl.

We are getting a score of 69% on internet.nl with the below standing values:
- Not reachable via modern internet address, or improvement possible (IPv6)
- Failed :Not all domain names signed (DNSSEC)
- Passed :Authenticity marks against email phishing (DMARC, DKIM and SPF)
- Failed :Mail server connection not or insufficiently secured (STARTTLS and DANE)

IPv6 addresses for mail server(s)close
Verdict:
At least one receiving mail server on your domain does not have an IPv6 address.

DNSSEC existenceclose
Verdict:
At least one of your mail server domains is insecure, because it is not DNSSEC signed.

DANE existenceclose
Verdict:
At least one of your mail server domains does not provide a TLSA record for DANE.