Here are some links that may help, but I can't really follow what they are doing. 2 factor verification with multiple usera on a gmail account 2+factor+verification+with+multiple+usera+on+a+gmeila+account&oq=2+factor+verification+with+multiple+usera+on+a+gmeila+account
It says
1. Navigate to ...
2. Select '2-Step Verification' under Signing in to Google.
3. Click Get Started.
4. Enter your Password.
Select Text Message as your option, and enter your phone number, and click NEXT.

I turned of 2-step verification and it gave me the following
I clicked text verification and entered your phone #
It returned the following

I didn't enter any of those devices I don't know how they got there. You then have to repeat the steps above and enter verify next to your phone number.
Share a Calendar:
Select a calendar under settings for my calendars
Click the calendar you want to share.
click on calendar settings - A window will open up on the right
scroll down to  "Share with specific people or groups"
You'll see you have full permissions.
You can add people at the bottom.

Select share with specific people to see who has access
You have access with full permissions to make changes.

click on mcbride cabinclick on calendar settings - A window will open up on the rightscroll down to  "Share with specific people or groups"You'll see you have full permissions.
Links: security
Data and Privacy
Set up 2-Factor Authentication for Shared Accounts in Google Workspace | NRVPC