You are not answering the question.
WHAT block did you see the difference on?
For example using the Xtreme theme, If I open a page editing page, and insert a Paragraph block, In the right column, there is a box Typography, and I see all the various size choices like you mentioned you see with a WP theme
ASLO if I click on the three dots right of Typography, it opens a sub menu, and I can chose to see the other options.
If I switch to twenty twenty one, I see the exact SAME options as in Xtreme
So I do not see the issue you are mentioning