Greetings Jackson,
It's our pleasure to assist you, based on your description, we understand that you can't see shared calendar in outlook desktop app. Microsoft have introduced a new option in the exchange account setting dialog: Turn on shared calendar improvements
As you mentioned that when you use outlook for web you don't face same issue, try the below steps:
- In Outlook, select File >Account Settings >Account Settings. You will see a list of your email accounts.
- Select the Microsoft Exchange account that you use to manage someone else's calendar and choose Change....
- Choose More Settings, followed by the Advanced tab.
- Select the checkbox next to: Turn on shared calendar improvements.
- Click on Apply then Ok
- Close and restart outlook
For Extra reference use this link": How to enable and disable the Outlook calendar sharing updates - Microsoft Support If the issue still persists, please kindly provide us previous requested information (screenshot of the issue and outlook version with build details), so we can check and assist you further. We are looking forward to your response Have a nice day!