Allow SSO intergration with O365. It would make using Atera helpdesk seamless for our end-users, if the HelpDesk is our in-house helpdesk.

sorry, but this question is a "not thought to an end one" once again. so why:
do you want to ask us for how our own O365 system (tenannt, users, etc.) should be integrated somehow?
or are you asking about "how can we manage multiple customer tenannts" like MS lighthouse and 3rd party cloud solutions would do?
so if YOU are asking us, could you please be that more exactly...

2 suggestions.

1. Intune:
Create and maintain templates for example: Antivirus, Disk Encryption, Firewall, Settings for automatically onboard OneDrive, Office packages, Endpoint Protection, and so on.
Use, maintain and deploy these templates to new and existing 365 tenants linked to Atera -> Customers.
Benefit -> Quick deployment of new tenants and easier maintaining exiting ones. Better security to end users.
(Spinpanel like solution)
Two way sync between 365 and Atera, let Intune do the roll out.
So you can also view the setting in Intune.

2. Integrate an 365 online Back-up solution like Altaro.
For customers in the EU make sure to also save the back-up in the EU due to EU rules and privacy law.

Better integration with InTune.
- Intune Application policies to push Homebrew apps to iOS and Chocolate apps to windows via the Atera Agent.
- Use Atera Agent to force policy check towards InTune to speed up InTune policy changes.

asynchronus updates of machines in patch management so you can create a large group of machines but have them update in serial so that you don't have many down at one for reboots etc

integrated azure login

Sponsor CIPP and integrate with them. CIPP.app / https://github.com/sponsors/KelvinTegelaar.

Monitoring sign ins.
Storage.
Backups.
Monitoring up and down statuses of O365

Pull client license info and automatically add to a ticket (or create a new one), effectively automating billing.

Allow to sync with a shared mailbox calendar

We don't see any need for an O365 integration.

I would really love to see that we would be to directly get notifications in Microsoft Teams when a new ticket has been created.

It is very simple because, every channel has its own email address.

Be able to on/off-board M365 users from ticket requests.

Manage users account, be able to lock users, manage litigation hold, mailbox permissions, forwarding, enable and disable apps, group and distro panagement...

Allow customer to have 1000 contacts more.

An option for OAuth authentication for SMTP mail server settings would be great.

MS 365 Defender integration to generate Atera alerts/tickets on Defender email alerts, real-time detections, etc.

Automated billing for licenses and license info

Allow customers to login to the portal with their Office365 credentials. Sync can already be made, so it wouldn't be hard to authenticate against Office365/Azure.
Especially useful when Atera is used internally as Servicedesk Software.

A few things....

1. an option to automatically export all tickets to calendar
2. an option to export ticket to calendar when creating a ticket.
3. to have client name showing instead/or with ticket number
4. There are bugs in saving default 365 address in admin section.