Command blocks, structure void, barrier and all the new blocks added to the creative menu in a new snapshot are not there

Open game menu > Options > Controls and enable "Operators Item Tab" 🙂.

This is mentioned in the 22w45a changelogs:

• Operator-only items now appear in a new Operator Utilities tab if you have both:

  • Operator Items Tab option in Controls menu set to ON

  • The required operator permissions