EntityFrameworkCore - how to convert a structure without a key field into a set of columns?

Question

C++ / C#

Good afternoon!
Please advise how to deal with this issue.
Based on the data structures of the VkNet library ( https://github.com/vknet/vk), I build database tables. VkNet has entities both with and without a key field. The VkNet.Model.User type has a key field, but the VkNet.Model.User.Education field with the VkNet.Model.Education type does not have a key field.
Previously, I used EntityFramework - which converted the VkNet.Model.User type into a User table, and converted the VkNet.Model.User.Education field with the VkNet.Model.Education type into User table columns, which looked like in the picture below.

Now I began to use EnityFrameworkCore, and it does not convert columns with a type without a key, but simply suggests ignoring them.
How can I implement the transformation in EnityFrameworkCore in the same way as I described it in the above for EntityFramework?
The project I'm working on is https://github.com/vailukhin/VkGroupSpider