@Małgorzata Thanks for posting in our Q&A.
For this issue, please note that the setting "allow widgets from work profile apps" is found in the device restrictions for the personally-owned work profile. It is not yet available for the Corporate-owned work profile.
https://vmlabblog.com/2021/04/how-to-add-widgets-for-work-profile-apps/
Note: Non-Microsoft link, just for the reference.
Hope it will help.
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